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Private Diffusion
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The Atomic Chat alternative built for image generation on Mac.

Before you type a single prompt, its analytics are already on.

Private Diffusion makes pictures on your Mac, iPhone, and iPad, and every model in it is retrained after shrinking so it holds its quality at the size your device can run. Atomic Chat is a chat app for local and cloud language models that can also generate images on a Mac. Private Diffusion is built for images alone, and it collects no data: nothing you type or generate reaches a Numen server.

Pre-order Private Diffusion on the App Store

The Short Version

Picture quality

Private DiffusionRetrained after shrinking with Quantization Aware Distillation (QAD) specifically to preserve image generation quality

Atomic ChatGGUF files with naive round to nearest (RTN) quantization

How it uses Apple Silicon

Private DiffusionGPU, Neural Engine, and the Neural Accelerators on M5 and A19 Pro and later

Atomic ChatGPU, no Neural Engine

What leaves your device

Private DiffusionCollects no data, not even crash reports

Atomic ChatPostHog and Sentry, on by default. Switching analytics off leaves Sentry session reports running.

The app itself

Private DiffusionSandboxed native Swift and C++, app and all models downloaded straight from Apple's servers

Atomic ChatUnsandboxed Tauri web app, direct download

Shrunk, Then Retrained Against the Original

Every Private Diffusion model is retrained after it's shrunk, so the small version on your Mac answers the way the full-size original would.

How it works

Running a big image model on a laptop means shrinking it. Atomic Chat offers each model as GGUF files and pre-selects Q4_K_M for you. Every one of our models is quantization-aware distilled (QAD): we shrink the weights to 4 bits (6 on Anima and Mage Flow Turbo), then keep training the small model against the full-size original until it answers the same way. The side-by-side below shows both apps' pictures under the same controls, so you can judge them for yourself.

SourcesNVIDIA: how quantization-aware training and distillation work

How We Shrink a Model

  1. Full-Size Original

    The model as its makers trained it, too big for a phone.

  2. Shrunk to Fit

    The weights are cut to a few bits each so the whole model fits on your device.

  3. Retrained Against the Original

    The small model keeps training until it answers the way the full-size one does.

Private Diffusion
Private Diffusion ships the retrained model.
Atomic Chat
Atomic Chat offers each model as GGUF files. It pre-selects Q4_K_M, and the largest it offers is Q8_0 for Flux.2 Klein 4B and Z-Image-Turbo and Q5_K_S for Krea 2 Turbo.

The Neural Engine at Work, Not Just the GPU

Private Diffusion puts the GPU and the Neural Engine to work, and on M5 and A19 Pro and later, the Neural Accelerators too. Atomic Chat's image engine runs on the GPU.

SourcesAtomic Chat 2.2.14 source: stable-diffusion.cpp, its only local image engine on a MacApple Newsroom: M6 and M5 Ultra, a Neural Accelerator in each GPU coreApple: iPhone 18 Pro tech specs, A20 Pro GPU with Neural Accelerators

Which Processors Do the Work

Private Diffusion

  • GPUUsed
  • Neural AcceleratorsM5 and A19 Pro and later
  • Neural EngineUsed

Atomic Chat

  • GPUUsed

No Analytics, Not Even on First Launch

Private Diffusion collects no data. Atomic Chat ships PostHog and Sentry with analytics on by default, and it sends its first analytics event about a second after launch, without asking you. Switching analytics off stops PostHog but not the Sentry session reports.

How it works

We captured a first launch of Atomic Chat from an empty state and decrypted the traffic. About a second in, with no click from the tester, the app sent PostHog an event carrying a distinct id, a device id, a session id, the OS, the app version, the screen size, and the current URL, with IP capture switched on. It also asked PostHog for its feature flags and sent Sentry its session data. There is no first-launch prompt, and analytics are on by default in Settings. Switching them off stops PostHog, while the Sentry session reports keep going. Atomic Chat ships PostHog and Sentry; Private Diffusion ships neither, has no analytics SDK or crash reporter, never asks for an account, and collects no data at all. Your prompts and images never reach a Numen server. If you're signed in to iCloud, your gallery mirrors to your own private iCloud.

SourcesAtomic Chat 2.2.14 source: analytics on by default, no first-launch promptAtomic Chat 2.2.14 telemetry source (PostHog, Sentry)

Atomic Chat's Settings window on the General tab: Chat Behavior section above an Analytics toggle labeled Help us improve, already on at first launch.
Atomic Chat 2.2.26, the General tab of Settings on a fresh first launch on 24 October 2026. Analytics comes on by default. The six-step setup never asked. Atomic Chat 2.2.14 source: analytics on by default, no first-launch prompt

A Native Mac App, Not a Web App in a Shell

Atomic Chat: a web app in a cross-platform desktop shell (Tauri), built for macOS, Windows, and Linux from one codebase. Private Diffusion: a native Swift and SwiftUI app; meticulously crafted Liquid Glass UI inspired by Apple's own apps and Human Interface Guidelines (HIG).

SourcesAtomic Chat for Mac binary, version 2.2.14: a Tauri app on the system WebKit viewAtomic Chat 2.2.14 code signature: no App Sandbox entitlement

Atomic Chat's Images screen on a Mac: Krea 2 Turbo at Q5_K_S selected, a prompt about a potter at the wheel, settings for size, steps, and seed, and the finished image of hands shaping clay.
Atomic Chat 2.2.14 on a Mac, the Images screen with Krea 2 Turbo selected. Checked October 19, 2026. Atomic Chat 2.2.14 code signature: no App Sandbox entitlement
Private Diffusion's Studio window on a Mac: a sidebar with Studio, Gallery, Model Library, and API Server, a generated lighthouse image, and a single prompt field with a Generate button.
Private Diffusion Studio on macOS 26, native Swift.

Built Safe, for You and Your Mac

Private Diffusion is a sandboxed native app, and every release passes Apple's App Review on its way to you. Atomic Chat for Mac runs outside the App Sandbox.

Your Mac

The App Sandbox is the wall macOS puts between an app and the rest of your files. Private Diffusion lives inside it, and each release goes through App Review before the App Store hands it to you. Atomic Chat for Mac is a direct download that runs outside the sandbox, with bun, uv, and cloudflared bundled beside it. Outside the sandbox an app can reach whatever you can reach, so anything that slips into it, or into the tools it bundles, through a supply chain attack can reach it too.

You, and Anyone Under 18

Private Diffusion asks the system one question through Apple's Declared Age Range: is this person 18? Under 18, every generated image is screened on the device, and anything flagged stays blurred. The answer never leaves the device, and neither does the picture.

The Same Models and Prompts, Side by Side

We ran Flux.2 Klein 4B, Z-Image-Turbo, and Krea 2 Turbo in both apps on one Mac, with the same prompts, the same seeds (1001, 2002, and 3003), the same 1024 x 1024 size, and each model's own step count. Each app ran its whole pipeline, from text encoder to final decode. For the first seed of every prompt, Private Diffusion's picture sits beside Atomic Chat's at its pre-selected quant and at the largest quant it offers, so you can compare them yourself. One exception: the Flux.2 Klein 4B neon-sign row shows the third seed, the only one where all three columns get both words right. A note under each row says what to look at.

Flux.2 Klein 4B

Flux.2 Klein 4B ran 4 steps at 1024x1024 with seeds 1001, 2002, 3003.

Prompt: Close-up of a pianist's hands on the keys of a grand piano, five fingers on each hand, warm stage light
Private Diffusion Flux.2 Klein 4B at QAD, prompt: Close-up of a pianist's hands on the keys of a grand piano, five fingers on each hand, warm stage light

Private Diffusion Flux.2 Klein 4B, QAD, v1.0.0 (29)

Atomic Chat Flux.2 Klein 4B at Q4_K_M, prompt: Close-up of a pianist's hands on the keys of a grand piano, five fingers on each hand, warm stage light

Atomic Chat Flux.2 Klein 4B, Q4_K_M, v2.2.14

Atomic Chat Flux.2 Klein 4B at Q8_0, prompt: Close-up of a pianist's hands on the keys of a grand piano, five fingers on each hand, warm stage light

Atomic Chat Flux.2 Klein 4B, Q8_0, v2.2.14

Private Diffusion shoots from behind the player, so the warm stage light rakes along the forearms and catches the open lid. Atomic Chat shoots across the keyboard with the fallboard in frame.

Prompt: A neon sign reading 'OPEN LATE' above a rainy diner door, photographed at night
Private Diffusion Flux.2 Klein 4B at QAD, prompt: A neon sign reading 'OPEN LATE' above a rainy diner door, photographed at night

Private Diffusion Flux.2 Klein 4B, QAD, v1.0.0 (29)

Atomic Chat Flux.2 Klein 4B at Q4_K_M, prompt: A neon sign reading 'OPEN LATE' above a rainy diner door, photographed at night

Atomic Chat Flux.2 Klein 4B, Q4_K_M, v2.2.14

Atomic Chat Flux.2 Klein 4B at Q8_0, prompt: A neon sign reading 'OPEN LATE' above a rainy diner door, photographed at night

Atomic Chat Flux.2 Klein 4B, Q8_0, v2.2.14

This is the seed-3003 row, and all three signs say OPEN LATE. Private Diffusion's diner has rain falling through the light, people at the counter inside, and wet pavement throwing the neon back. Atomic Chat's rain shows mostly as drops on the glass.

Prompt: Studio portrait of an elderly fisherman with a weathered face and white beard, soft window light
Private Diffusion Flux.2 Klein 4B at QAD, prompt: Studio portrait of an elderly fisherman with a weathered face and white beard, soft window light

Private Diffusion Flux.2 Klein 4B, QAD, v1.0.0 (29)

Atomic Chat Flux.2 Klein 4B at Q4_K_M, prompt: Studio portrait of an elderly fisherman with a weathered face and white beard, soft window light

Atomic Chat Flux.2 Klein 4B, Q4_K_M, v2.2.14

Atomic Chat Flux.2 Klein 4B at Q8_0, prompt: Studio portrait of an elderly fisherman with a weathered face and white beard, soft window light

Atomic Chat Flux.2 Klein 4B, Q8_0, v2.2.14

The prompt asks for soft window light. In Private Diffusion's portrait the light comes from the window on the left and falls off across the face, so the far cheek sits in shadow. Atomic Chat lights the face evenly from the front.

Prompt: Macro photo of a hand-woven wool blanket in red and cream stripes, individual fibers visible
Private Diffusion Flux.2 Klein 4B at QAD, prompt: Macro photo of a hand-woven wool blanket in red and cream stripes, individual fibers visible

Private Diffusion Flux.2 Klein 4B, QAD, v1.0.0 (29)

Atomic Chat Flux.2 Klein 4B at Q4_K_M, prompt: Macro photo of a hand-woven wool blanket in red and cream stripes, individual fibers visible

Atomic Chat Flux.2 Klein 4B, Q4_K_M, v2.2.14

Atomic Chat Flux.2 Klein 4B at Q8_0, prompt: Macro photo of a hand-woven wool blanket in red and cream stripes, individual fibers visible

Atomic Chat Flux.2 Klein 4B, Q8_0, v2.2.14

The prompt says hand-woven. Private Diffusion's blanket is woven, and you can follow the red and cream yarn over and under. Atomic Chat's blanket is knitted, in rows of loops.

Prompt: A fern-covered forest floor after rain, dew on every leaf, shallow depth of field
Private Diffusion Flux.2 Klein 4B at QAD, prompt: A fern-covered forest floor after rain, dew on every leaf, shallow depth of field

Private Diffusion Flux.2 Klein 4B, QAD, v1.0.0 (29)

Atomic Chat Flux.2 Klein 4B at Q4_K_M, prompt: A fern-covered forest floor after rain, dew on every leaf, shallow depth of field

Atomic Chat Flux.2 Klein 4B, Q4_K_M, v2.2.14

Atomic Chat Flux.2 Klein 4B at Q8_0, prompt: A fern-covered forest floor after rain, dew on every leaf, shallow depth of field

Atomic Chat Flux.2 Klein 4B, Q8_0, v2.2.14

All three put dew on the fronds. Private Diffusion keeps the rain falling through the frame and lets the trunks fade into mist, so the picture reads as a wet forest rather than a plant study.

Prompt: Portrait of a woman with long curly auburn hair backlit by the setting sun, individual strands catching light
Private Diffusion Flux.2 Klein 4B at QAD, prompt: Portrait of a woman with long curly auburn hair backlit by the setting sun, individual strands catching light

Private Diffusion Flux.2 Klein 4B, QAD, v1.0.0 (29)

Atomic Chat Flux.2 Klein 4B at Q4_K_M, prompt: Portrait of a woman with long curly auburn hair backlit by the setting sun, individual strands catching light

Atomic Chat Flux.2 Klein 4B, Q4_K_M, v2.2.14

Atomic Chat Flux.2 Klein 4B at Q8_0, prompt: Portrait of a woman with long curly auburn hair backlit by the setting sun, individual strands catching light

Atomic Chat Flux.2 Klein 4B, Q8_0, v2.2.14

Both apps put the sun behind her. Private Diffusion turns her a quarter away from the lens, so the backlight rims the curls on one side and the sky stays in the frame. Atomic Chat lights the whole head from behind until the edges glow.

Prompt: A Gothic cathedral nave seen from the entrance, ribbed vaults, stained glass, symmetrical composition
Private Diffusion Flux.2 Klein 4B at QAD, prompt: A Gothic cathedral nave seen from the entrance, ribbed vaults, stained glass, symmetrical composition

Private Diffusion Flux.2 Klein 4B, QAD, v1.0.0 (29)

Atomic Chat Flux.2 Klein 4B at Q4_K_M, prompt: A Gothic cathedral nave seen from the entrance, ribbed vaults, stained glass, symmetrical composition

Atomic Chat Flux.2 Klein 4B, Q4_K_M, v2.2.14

Atomic Chat Flux.2 Klein 4B at Q8_0, prompt: A Gothic cathedral nave seen from the entrance, ribbed vaults, stained glass, symmetrical composition

Atomic Chat Flux.2 Klein 4B, Q8_0, v2.2.14

Private Diffusion's nave has daylight pouring through the clerestory and a visitor at the foot of a pier for scale. Atomic Chat's nave is empty and centered on the great west window.

Prompt: A wooden kitchen table with a red teapot, three lemons, a blue ceramic bowl of walnuts, and a folded newspaper
Private Diffusion Flux.2 Klein 4B at QAD, prompt: A wooden kitchen table with a red teapot, three lemons, a blue ceramic bowl of walnuts, and a folded newspaper

Private Diffusion Flux.2 Klein 4B, QAD, v1.0.0 (29)

Atomic Chat Flux.2 Klein 4B at Q4_K_M, prompt: A wooden kitchen table with a red teapot, three lemons, a blue ceramic bowl of walnuts, and a folded newspaper

Atomic Chat Flux.2 Klein 4B, Q4_K_M, v2.2.14

Atomic Chat Flux.2 Klein 4B at Q8_0, prompt: A wooden kitchen table with a red teapot, three lemons, a blue ceramic bowl of walnuts, and a folded newspaper

Atomic Chat Flux.2 Klein 4B, Q8_0, v2.2.14

Private Diffusion pulls back to show the kitchen behind the table, with the sink and the window in frame. Atomic Chat crops to the tabletop and the stove.

Prompt: A hand-lettered chalkboard menu reading 'SOUP OF THE DAY' with a small drawing of a bowl beneath
Private Diffusion Flux.2 Klein 4B at QAD, prompt: A hand-lettered chalkboard menu reading 'SOUP OF THE DAY' with a small drawing of a bowl beneath

Private Diffusion Flux.2 Klein 4B, QAD, v1.0.0 (29)

Atomic Chat Flux.2 Klein 4B at Q4_K_M, prompt: A hand-lettered chalkboard menu reading 'SOUP OF THE DAY' with a small drawing of a bowl beneath

Atomic Chat Flux.2 Klein 4B, Q4_K_M, v2.2.14

Atomic Chat Flux.2 Klein 4B at Q8_0, prompt: A hand-lettered chalkboard menu reading 'SOUP OF THE DAY' with a small drawing of a bowl beneath

Atomic Chat Flux.2 Klein 4B, Q8_0, v2.2.14

None of the three spells the whole menu. Private Diffusion's board is the one that looks used, with ghost strokes from the last menu and chalk dust in the corners.

Prompt: A potter shaping clay on a wheel, both hands visible, wet clay on the fingers
Private Diffusion Flux.2 Klein 4B at QAD, prompt: A potter shaping clay on a wheel, both hands visible, wet clay on the fingers

Private Diffusion Flux.2 Klein 4B, QAD, v1.0.0 (29)

Atomic Chat Flux.2 Klein 4B at Q4_K_M, prompt: A potter shaping clay on a wheel, both hands visible, wet clay on the fingers

Atomic Chat Flux.2 Klein 4B, Q4_K_M, v2.2.14

Atomic Chat Flux.2 Klein 4B at Q8_0, prompt: A potter shaping clay on a wheel, both hands visible, wet clay on the fingers

Atomic Chat Flux.2 Klein 4B, Q8_0, v2.2.14

Private Diffusion steps back to show the potter bent over the wheel, face and both forearms in the shot and clay on the apron. Atomic Chat crops to the hands and the rim.

Details Up Close

Hands

Hands detail from Private Diffusion Flux.2 Klein 4B at QAD
Private Diffusion Flux.2 Klein 4B, QAD, v1.0.0 (29)
Hands detail from Atomic Chat Flux.2 Klein 4B at Q4_K_M
Atomic Chat Flux.2 Klein 4B, Q4_K_M, v2.2.14
Hands detail from Atomic Chat Flux.2 Klein 4B at Q8_0
Atomic Chat Flux.2 Klein 4B, Q8_0, v2.2.14

Lettering

Lettering detail from Private Diffusion Flux.2 Klein 4B at QAD
Private Diffusion Flux.2 Klein 4B, QAD, v1.0.0 (29)
Lettering detail from Atomic Chat Flux.2 Klein 4B at Q4_K_M
Atomic Chat Flux.2 Klein 4B, Q4_K_M, v2.2.14
Lettering detail from Atomic Chat Flux.2 Klein 4B at Q8_0
Atomic Chat Flux.2 Klein 4B, Q8_0, v2.2.14

Texture

Texture detail from Private Diffusion Flux.2 Klein 4B at QAD
Private Diffusion Flux.2 Klein 4B, QAD, v1.0.0 (29)
Texture detail from Atomic Chat Flux.2 Klein 4B at Q4_K_M
Atomic Chat Flux.2 Klein 4B, Q4_K_M, v2.2.14
Texture detail from Atomic Chat Flux.2 Klein 4B at Q8_0
Atomic Chat Flux.2 Klein 4B, Q8_0, v2.2.14

Z-Image-Turbo

Z-Image-Turbo ran 9 steps at 1024x1024 with seeds 1001, 2002, 3003.

Prompt: Close-up of a pianist's hands on the keys of a grand piano, five fingers on each hand, warm stage light
Private Diffusion Z-Image-Turbo at QAD, prompt: Close-up of a pianist's hands on the keys of a grand piano, five fingers on each hand, warm stage light

Private Diffusion Z-Image-Turbo, QAD, v1.0.0 (29)

Atomic Chat Z-Image-Turbo at Q4_K_M, prompt: Close-up of a pianist's hands on the keys of a grand piano, five fingers on each hand, warm stage light

Atomic Chat Z-Image-Turbo, Q4_K_M, v2.2.14

Atomic Chat Z-Image-Turbo at Q8_0, prompt: Close-up of a pianist's hands on the keys of a grand piano, five fingers on each hand, warm stage light

Atomic Chat Z-Image-Turbo, Q8_0, v2.2.14

Private Diffusion's pianist has five fingers on each hand, curved over the keys the way a player holds them, with the stage light warming the skin. Atomic Chat's fingers stretch long and flat, and the near hand crowds the keys.

Prompt: A neon sign reading 'OPEN LATE' above a rainy diner door, photographed at night
Private Diffusion Z-Image-Turbo at QAD, prompt: A neon sign reading 'OPEN LATE' above a rainy diner door, photographed at night

Private Diffusion Z-Image-Turbo, QAD, v1.0.0 (29)

Atomic Chat Z-Image-Turbo at Q4_K_M, prompt: A neon sign reading 'OPEN LATE' above a rainy diner door, photographed at night

Atomic Chat Z-Image-Turbo, Q4_K_M, v2.2.14

Atomic Chat Z-Image-Turbo at Q8_0, prompt: A neon sign reading 'OPEN LATE' above a rainy diner door, photographed at night

Atomic Chat Z-Image-Turbo, Q8_0, v2.2.14

All three read OPEN LATE. Private Diffusion builds the sign the way a diner sign is built, red letters inside a blue tube border, with rain streaking the door glass and the pavement shining. Atomic Chat puts two people in the doorway.

Prompt: Studio portrait of an elderly fisherman with a weathered face and white beard, soft window light
Private Diffusion Z-Image-Turbo at QAD, prompt: Studio portrait of an elderly fisherman with a weathered face and white beard, soft window light

Private Diffusion Z-Image-Turbo, QAD, v1.0.0 (29)

Atomic Chat Z-Image-Turbo at Q4_K_M, prompt: Studio portrait of an elderly fisherman with a weathered face and white beard, soft window light

Atomic Chat Z-Image-Turbo, Q4_K_M, v2.2.14

Atomic Chat Z-Image-Turbo at Q8_0, prompt: Studio portrait of an elderly fisherman with a weathered face and white beard, soft window light

Atomic Chat Z-Image-Turbo, Q8_0, v2.2.14

Soft window light again. Private Diffusion lights the fisherman from the side, so the brow and the cheekbone throw shadow and the beard has depth. Atomic Chat lights the face flat from the front against a washed-out window.

Prompt: Macro photo of a hand-woven wool blanket in red and cream stripes, individual fibers visible
Private Diffusion Z-Image-Turbo at QAD, prompt: Macro photo of a hand-woven wool blanket in red and cream stripes, individual fibers visible

Private Diffusion Z-Image-Turbo, QAD, v1.0.0 (29)

Atomic Chat Z-Image-Turbo at Q4_K_M, prompt: Macro photo of a hand-woven wool blanket in red and cream stripes, individual fibers visible

Atomic Chat Z-Image-Turbo, Q4_K_M, v2.2.14

Atomic Chat Z-Image-Turbo at Q8_0, prompt: Macro photo of a hand-woven wool blanket in red and cream stripes, individual fibers visible

Atomic Chat Z-Image-Turbo, Q8_0, v2.2.14

Private Diffusion's blanket is woven, and single fibers lift off the yarn, which is what the prompt asks for. Atomic Chat's is a smooth knit with clean stripes and no fiber you can pick out.

Prompt: A fern-covered forest floor after rain, dew on every leaf, shallow depth of field
Private Diffusion Z-Image-Turbo at QAD, prompt: A fern-covered forest floor after rain, dew on every leaf, shallow depth of field

Private Diffusion Z-Image-Turbo, QAD, v1.0.0 (29)

Atomic Chat Z-Image-Turbo at Q4_K_M, prompt: A fern-covered forest floor after rain, dew on every leaf, shallow depth of field

Atomic Chat Z-Image-Turbo, Q4_K_M, v2.2.14

Atomic Chat Z-Image-Turbo at Q8_0, prompt: A fern-covered forest floor after rain, dew on every leaf, shallow depth of field

Atomic Chat Z-Image-Turbo, Q8_0, v2.2.14

Private Diffusion gives you the forest floor: several ferns at different distances, with the focus soft behind the front frond. Atomic Chat centers one frond and puts the dew on it.

Prompt: Portrait of a woman with long curly auburn hair backlit by the setting sun, individual strands catching light
Private Diffusion Z-Image-Turbo at QAD, prompt: Portrait of a woman with long curly auburn hair backlit by the setting sun, individual strands catching light

Private Diffusion Z-Image-Turbo, QAD, v1.0.0 (29)

Atomic Chat Z-Image-Turbo at Q4_K_M, prompt: Portrait of a woman with long curly auburn hair backlit by the setting sun, individual strands catching light

Atomic Chat Z-Image-Turbo, Q4_K_M, v2.2.14

Atomic Chat Z-Image-Turbo at Q8_0, prompt: Portrait of a woman with long curly auburn hair backlit by the setting sun, individual strands catching light

Atomic Chat Z-Image-Turbo, Q8_0, v2.2.14

The prompt asks for a portrait. Private Diffusion shows her face, three-quarter to the lens, with the low sun lighting every flyaway strand. Atomic Chat shows the back of her head.

Prompt: A Gothic cathedral nave seen from the entrance, ribbed vaults, stained glass, symmetrical composition
Private Diffusion Z-Image-Turbo at QAD, prompt: A Gothic cathedral nave seen from the entrance, ribbed vaults, stained glass, symmetrical composition

Private Diffusion Z-Image-Turbo, QAD, v1.0.0 (29)

Atomic Chat Z-Image-Turbo at Q4_K_M, prompt: A Gothic cathedral nave seen from the entrance, ribbed vaults, stained glass, symmetrical composition

Atomic Chat Z-Image-Turbo, Q4_K_M, v2.2.14

Atomic Chat Z-Image-Turbo at Q8_0, prompt: A Gothic cathedral nave seen from the entrance, ribbed vaults, stained glass, symmetrical composition

Atomic Chat Z-Image-Turbo, Q8_0, v2.2.14

Private Diffusion's nave is shot from the entrance with a normal lens, so the piers stand straight and the vaults recede to the altar. Atomic Chat's is wider, and the columns bow toward the edges of the frame.

Prompt: A wooden kitchen table with a red teapot, three lemons, a blue ceramic bowl of walnuts, and a folded newspaper
Private Diffusion Z-Image-Turbo at QAD, prompt: A wooden kitchen table with a red teapot, three lemons, a blue ceramic bowl of walnuts, and a folded newspaper

Private Diffusion Z-Image-Turbo, QAD, v1.0.0 (29)

Atomic Chat Z-Image-Turbo at Q4_K_M, prompt: A wooden kitchen table with a red teapot, three lemons, a blue ceramic bowl of walnuts, and a folded newspaper

Atomic Chat Z-Image-Turbo, Q4_K_M, v2.2.14

Atomic Chat Z-Image-Turbo at Q8_0, prompt: A wooden kitchen table with a red teapot, three lemons, a blue ceramic bowl of walnuts, and a folded newspaper

Atomic Chat Z-Image-Turbo, Q8_0, v2.2.14

All three set out every item on the list, three lemons included. Private Diffusion moves in closer, so the lemons and the walnut bowl fill the front of the frame.

Prompt: A hand-lettered chalkboard menu reading 'SOUP OF THE DAY' with a small drawing of a bowl beneath
Private Diffusion Z-Image-Turbo at QAD, prompt: A hand-lettered chalkboard menu reading 'SOUP OF THE DAY' with a small drawing of a bowl beneath

Private Diffusion Z-Image-Turbo, QAD, v1.0.0 (29)

Atomic Chat Z-Image-Turbo at Q4_K_M, prompt: A hand-lettered chalkboard menu reading 'SOUP OF THE DAY' with a small drawing of a bowl beneath

Atomic Chat Z-Image-Turbo, Q4_K_M, v2.2.14

Atomic Chat Z-Image-Turbo at Q8_0, prompt: A hand-lettered chalkboard menu reading 'SOUP OF THE DAY' with a small drawing of a bowl beneath

Atomic Chat Z-Image-Turbo, Q8_0, v2.2.14

All three boards read SOUP OF THE DAY. Private Diffusion's letters are heavier chalk strokes, and the bowl beneath is drawn full, with steam rising.

Prompt: A potter shaping clay on a wheel, both hands visible, wet clay on the fingers
Private Diffusion Z-Image-Turbo at QAD, prompt: A potter shaping clay on a wheel, both hands visible, wet clay on the fingers

Private Diffusion Z-Image-Turbo, QAD, v1.0.0 (29)

Atomic Chat Z-Image-Turbo at Q4_K_M, prompt: A potter shaping clay on a wheel, both hands visible, wet clay on the fingers

Atomic Chat Z-Image-Turbo, Q4_K_M, v2.2.14

Atomic Chat Z-Image-Turbo at Q8_0, prompt: A potter shaping clay on a wheel, both hands visible, wet clay on the fingers

Atomic Chat Z-Image-Turbo, Q8_0, v2.2.14

Private Diffusion's potter has a pot rising off the wheel and ten fingers wet with slip. Atomic Chat's hands sit on a low mound of clay, and the fingers run together.

Details Up Close

Hands

Hands detail from Private Diffusion Z-Image-Turbo at QAD
Private Diffusion Z-Image-Turbo, QAD, v1.0.0 (29)
Hands detail from Atomic Chat Z-Image-Turbo at Q4_K_M
Atomic Chat Z-Image-Turbo, Q4_K_M, v2.2.14
Hands detail from Atomic Chat Z-Image-Turbo at Q8_0
Atomic Chat Z-Image-Turbo, Q8_0, v2.2.14

Lettering

Lettering detail from Private Diffusion Z-Image-Turbo at QAD
Private Diffusion Z-Image-Turbo, QAD, v1.0.0 (29)
Lettering detail from Atomic Chat Z-Image-Turbo at Q4_K_M
Atomic Chat Z-Image-Turbo, Q4_K_M, v2.2.14
Lettering detail from Atomic Chat Z-Image-Turbo at Q8_0
Atomic Chat Z-Image-Turbo, Q8_0, v2.2.14

Texture

Texture detail from Private Diffusion Z-Image-Turbo at QAD
Private Diffusion Z-Image-Turbo, QAD, v1.0.0 (29)
Texture detail from Atomic Chat Z-Image-Turbo at Q4_K_M
Atomic Chat Z-Image-Turbo, Q4_K_M, v2.2.14
Texture detail from Atomic Chat Z-Image-Turbo at Q8_0
Atomic Chat Z-Image-Turbo, Q8_0, v2.2.14

Krea 2 Turbo

Krea 2 Turbo ran 8 steps at 1024x1024 with seeds 1001, 2002, 3003.

Prompt: Close-up of a pianist's hands on the keys of a grand piano, five fingers on each hand, warm stage light
Private Diffusion Krea 2 Turbo at QAD, prompt: Close-up of a pianist's hands on the keys of a grand piano, five fingers on each hand, warm stage light

Private Diffusion Krea 2 Turbo, QAD, v1.0.0 (29)

Atomic Chat Krea 2 Turbo at Q4_K_M, prompt: Close-up of a pianist's hands on the keys of a grand piano, five fingers on each hand, warm stage light

Atomic Chat Krea 2 Turbo, Q4_K_M, v2.2.14

Atomic Chat Krea 2 Turbo at Q5_K_S, prompt: Close-up of a pianist's hands on the keys of a grand piano, five fingers on each hand, warm stage light

Atomic Chat Krea 2 Turbo, Q5_K_S, v2.2.14

Private Diffusion's near hand is sharp down to the knuckles, with the far hand soft in the depth of field. Atomic Chat's near hand smears where the fingers meet the keys.

Prompt: A neon sign reading 'OPEN LATE' above a rainy diner door, photographed at night
Private Diffusion Krea 2 Turbo at QAD, prompt: A neon sign reading 'OPEN LATE' above a rainy diner door, photographed at night

Private Diffusion Krea 2 Turbo, QAD, v1.0.0 (29)

Atomic Chat Krea 2 Turbo at Q4_K_M, prompt: A neon sign reading 'OPEN LATE' above a rainy diner door, photographed at night

Atomic Chat Krea 2 Turbo, Q4_K_M, v2.2.14

Atomic Chat Krea 2 Turbo at Q5_K_S, prompt: A neon sign reading 'OPEN LATE' above a rainy diner door, photographed at night

Atomic Chat Krea 2 Turbo, Q5_K_S, v2.2.14

All three read OPEN LATE in a boxed sign. Private Diffusion keeps the tubes crisp and the diner behind the glass legible. Atomic Chat's frame is softer, as if the lens had fogged.

Prompt: Studio portrait of an elderly fisherman with a weathered face and white beard, soft window light
Private Diffusion Krea 2 Turbo at QAD, prompt: Studio portrait of an elderly fisherman with a weathered face and white beard, soft window light

Private Diffusion Krea 2 Turbo, QAD, v1.0.0 (29)

Atomic Chat Krea 2 Turbo at Q4_K_M, prompt: Studio portrait of an elderly fisherman with a weathered face and white beard, soft window light

Atomic Chat Krea 2 Turbo, Q4_K_M, v2.2.14

Atomic Chat Krea 2 Turbo at Q5_K_S, prompt: Studio portrait of an elderly fisherman with a weathered face and white beard, soft window light

Atomic Chat Krea 2 Turbo, Q5_K_S, v2.2.14

Private Diffusion keeps the texture in the skin and a soft shadow down one side of the face. Atomic Chat lights him flat, and the picture goes grey.

Prompt: Macro photo of a hand-woven wool blanket in red and cream stripes, individual fibers visible
Private Diffusion Krea 2 Turbo at QAD, prompt: Macro photo of a hand-woven wool blanket in red and cream stripes, individual fibers visible

Private Diffusion Krea 2 Turbo, QAD, v1.0.0 (29)

Atomic Chat Krea 2 Turbo at Q4_K_M, prompt: Macro photo of a hand-woven wool blanket in red and cream stripes, individual fibers visible

Atomic Chat Krea 2 Turbo, Q4_K_M, v2.2.14

Atomic Chat Krea 2 Turbo at Q5_K_S, prompt: Macro photo of a hand-woven wool blanket in red and cream stripes, individual fibers visible

Atomic Chat Krea 2 Turbo, Q5_K_S, v2.2.14

Private Diffusion's blanket shows the selvedge and fringe of a hand-woven piece, with the twill visible and single fibers lifting off the yarn. Atomic Chat shows a flat stretch of plain weave.

Prompt: A fern-covered forest floor after rain, dew on every leaf, shallow depth of field
Private Diffusion Krea 2 Turbo at QAD, prompt: A fern-covered forest floor after rain, dew on every leaf, shallow depth of field

Private Diffusion Krea 2 Turbo, QAD, v1.0.0 (29)

Atomic Chat Krea 2 Turbo at Q4_K_M, prompt: A fern-covered forest floor after rain, dew on every leaf, shallow depth of field

Atomic Chat Krea 2 Turbo, Q4_K_M, v2.2.14

Atomic Chat Krea 2 Turbo at Q5_K_S, prompt: A fern-covered forest floor after rain, dew on every leaf, shallow depth of field

Atomic Chat Krea 2 Turbo, Q5_K_S, v2.2.14

The closest row in the set: all three show dewy ferns in a soft forest. Private Diffusion's front frond holds the sharpest drops, and the trunks behind fall off faster into the dark.

Prompt: Portrait of a woman with long curly auburn hair backlit by the setting sun, individual strands catching light
Private Diffusion Krea 2 Turbo at QAD, prompt: Portrait of a woman with long curly auburn hair backlit by the setting sun, individual strands catching light

Private Diffusion Krea 2 Turbo, QAD, v1.0.0 (29)

Atomic Chat Krea 2 Turbo at Q4_K_M, prompt: Portrait of a woman with long curly auburn hair backlit by the setting sun, individual strands catching light

Atomic Chat Krea 2 Turbo, Q4_K_M, v2.2.14

Atomic Chat Krea 2 Turbo at Q5_K_S, prompt: Portrait of a woman with long curly auburn hair backlit by the setting sun, individual strands catching light

Atomic Chat Krea 2 Turbo, Q5_K_S, v2.2.14

Both apps catch the strands. Private Diffusion's backlight wraps further around the curls, and each stray strand at the edge catches its own line of light.

Prompt: A Gothic cathedral nave seen from the entrance, ribbed vaults, stained glass, symmetrical composition
Private Diffusion Krea 2 Turbo at QAD, prompt: A Gothic cathedral nave seen from the entrance, ribbed vaults, stained glass, symmetrical composition

Private Diffusion Krea 2 Turbo, QAD, v1.0.0 (29)

Atomic Chat Krea 2 Turbo at Q4_K_M, prompt: A Gothic cathedral nave seen from the entrance, ribbed vaults, stained glass, symmetrical composition

Atomic Chat Krea 2 Turbo, Q4_K_M, v2.2.14

Atomic Chat Krea 2 Turbo at Q5_K_S, prompt: A Gothic cathedral nave seen from the entrance, ribbed vaults, stained glass, symmetrical composition

Atomic Chat Krea 2 Turbo, Q5_K_S, v2.2.14

Private Diffusion's nave has the late light coming in through the side windows and falling across the pews in bands. Atomic Chat's nave is lit evenly from end to end.

Prompt: A wooden kitchen table with a red teapot, three lemons, a blue ceramic bowl of walnuts, and a folded newspaper
Private Diffusion Krea 2 Turbo at QAD, prompt: A wooden kitchen table with a red teapot, three lemons, a blue ceramic bowl of walnuts, and a folded newspaper

Private Diffusion Krea 2 Turbo, QAD, v1.0.0 (29)

Atomic Chat Krea 2 Turbo at Q4_K_M, prompt: A wooden kitchen table with a red teapot, three lemons, a blue ceramic bowl of walnuts, and a folded newspaper

Atomic Chat Krea 2 Turbo, Q4_K_M, v2.2.14

Atomic Chat Krea 2 Turbo at Q5_K_S, prompt: A wooden kitchen table with a red teapot, three lemons, a blue ceramic bowl of walnuts, and a folded newspaper

Atomic Chat Krea 2 Turbo, Q5_K_S, v2.2.14

Both apps count correctly here. Private Diffusion's teapot is a teapot. Atomic Chat's is a stovetop kettle with a bail handle.

Prompt: A hand-lettered chalkboard menu reading 'SOUP OF THE DAY' with a small drawing of a bowl beneath
Private Diffusion Krea 2 Turbo at QAD, prompt: A hand-lettered chalkboard menu reading 'SOUP OF THE DAY' with a small drawing of a bowl beneath

Private Diffusion Krea 2 Turbo, QAD, v1.0.0 (29)

Atomic Chat Krea 2 Turbo at Q4_K_M, prompt: A hand-lettered chalkboard menu reading 'SOUP OF THE DAY' with a small drawing of a bowl beneath

Atomic Chat Krea 2 Turbo, Q4_K_M, v2.2.14

Atomic Chat Krea 2 Turbo at Q5_K_S, prompt: A hand-lettered chalkboard menu reading 'SOUP OF THE DAY' with a small drawing of a bowl beneath

Atomic Chat Krea 2 Turbo, Q5_K_S, v2.2.14

All three read SOUP OF THE DAY. Private Diffusion draws it on an actual chalkboard, with dust, smudges, and a filled bowl beneath. Atomic Chat's lettering floats on flat black.

Prompt: A potter shaping clay on a wheel, both hands visible, wet clay on the fingers
Private Diffusion Krea 2 Turbo at QAD, prompt: A potter shaping clay on a wheel, both hands visible, wet clay on the fingers

Private Diffusion Krea 2 Turbo, QAD, v1.0.0 (29)

Atomic Chat Krea 2 Turbo at Q4_K_M, prompt: A potter shaping clay on a wheel, both hands visible, wet clay on the fingers

Atomic Chat Krea 2 Turbo, Q4_K_M, v2.2.14

Atomic Chat Krea 2 Turbo at Q5_K_S, prompt: A potter shaping clay on a wheel, both hands visible, wet clay on the fingers

Atomic Chat Krea 2 Turbo, Q5_K_S, v2.2.14

Private Diffusion's potter has two hands with the right number of fingers, and the wet clay sits in the creases. Atomic Chat's pre-selected quant runs the fingers together into one shape.

Details Up Close

Hands

Hands detail from Private Diffusion Krea 2 Turbo at QAD
Private Diffusion Krea 2 Turbo, QAD, v1.0.0 (29)
Hands detail from Atomic Chat Krea 2 Turbo at Q4_K_M
Atomic Chat Krea 2 Turbo, Q4_K_M, v2.2.14
Hands detail from Atomic Chat Krea 2 Turbo at Q5_K_S
Atomic Chat Krea 2 Turbo, Q5_K_S, v2.2.14

Lettering

Lettering detail from Private Diffusion Krea 2 Turbo at QAD
Private Diffusion Krea 2 Turbo, QAD, v1.0.0 (29)
Lettering detail from Atomic Chat Krea 2 Turbo at Q4_K_M
Atomic Chat Krea 2 Turbo, Q4_K_M, v2.2.14
Lettering detail from Atomic Chat Krea 2 Turbo at Q5_K_S
Atomic Chat Krea 2 Turbo, Q5_K_S, v2.2.14

Texture

Texture detail from Private Diffusion Krea 2 Turbo at QAD
Private Diffusion Krea 2 Turbo, QAD, v1.0.0 (29)
Texture detail from Atomic Chat Krea 2 Turbo at Q4_K_M
Atomic Chat Krea 2 Turbo, Q4_K_M, v2.2.14
Texture detail from Atomic Chat Krea 2 Turbo at Q5_K_S
Atomic Chat Krea 2 Turbo, Q5_K_S, v2.2.14
How We Tested

Every image was made on a MacBook Pro (Mac16,6), Apple M4 Max, 64 GB, running macOS 27.0.1 (26A434). Both apps ran the same model with the same prompt, the same seeds (1001, 2002, 3003), the same 1024x1024 size, and that model's own step count. Private Diffusion's images were generated at Max quality through its local API server, with PNG output. Atomic Chat's images were generated in its app and taken from the PNG it writes. The same seed number does not start two different engines from the same noise, so compare the pictures, not the pixels.

Before review, the PNGs from both apps were normalized the same way, so no picture was handled differently from the others.

Which One Is for You

Pick Atomic Chat If

  • You want one app for chatting with local language models
  • You want cloud and local models side by side in the same app
  • You also work on Windows, Linux, or Android

Pick Private Diffusion If

  • You care about image generation quality
  • You want more than three image models to choose from
  • You care about safety and security, yours and your Mac's

Want an image app that sends nothing, not even on first launch? Pick Private Diffusion.

Private Diffusion and Atomic Chat Side by Side

How the two apps compare on Apple Silicon, as of the date in the sources below.
What you getPrivate DiffusionAtomic Chat
How models are shrunkRetrained after shrinking (QAD)GGUF files, Q4_K_M pre-selected
Processors it usesGPU and Neural EngineGPU through Metal
Data the app collectsNoneDevice and session IDs, OS, screen size, and IP address, on by default. Sentry session reports continue after you switch analytics off.
Analytics SDKsNonePostHog and Sentry
How it's builtNative Swift with Liquid GlassWeb app in a Tauri desktop shell
App SandboxYes, with hardened runtimeNo, with hardened runtime
Runs oniPhone, iPad, and MacMac, Windows, and Linux; separate iPhone, iPad, and Android apps
Getting startedDownload a model, type a promptDownload the engine and a model, type a prompt
ModelsCurated, each tuned for your deviceImage models from its catalog, as GGUF files
Compare all
How the apps compare on Apple Silicon.
What you getPrivate DiffusionDraw ThingsComfyUIAtomic Chat
How models are shrunkRetrained after shrinking (QAD)Compressed after training, no retrainingDepends on the checkpoint you loadGGUF files, Q4_K_M pre-selected
Processors it usesGPU and Neural EngineGPU; Neural Engine for select modelsGPU through PyTorch MPSGPU through Metal
Data the app collectsNonePurchases, User Content, IdentifiersUsage and error telemetry, on by defaultDevice and session IDs, OS, screen size, and IP address, on by default. Sentry session reports continue after you switch analytics off.
Analytics SDKsNoneNone named in its policyPostHog and Datadog RUMPostHog and Sentry
How it's builtNative Swift with Liquid GlassMac Catalyst build of its iPad appElectron with bundled PythonWeb app in a Tauri desktop shell
App SandboxYes, with hardened runtimeYesNoNo, with hardened runtime
Runs oniPhone, iPad, and MaciPhone, iPad, and MacMac, Windows, and Linux; no iPhone or iPadMac, Windows, and Linux; separate iPhone, iPad, and Android apps
Getting startedDownload a model, type a promptPick a model, then tune the settingsPython install, then a node graphDownload the engine and a model, type a prompt
ModelsCurated, each tuned for your device248 catalog entriesAny checkpoint you findImage models from its catalog, as GGUF files

Atomic Chat Alternative FAQ

  • If you want an app built for pictures, Private Diffusion. It puts the GPU and the Neural Engine to work, and on M5 and A19 Pro and later, the Neural Accelerators too. Every model is retrained after shrinking to hold its quality, and the app collects no data. Atomic Chat is still the pick if you want one app for local and cloud chat models.

  • Some of them, yes: Flux.2 Klein 4B, Z-Image-Turbo, and Krea 2 Turbo run in both. Atomic Chat downloads them as GGUF files and pre-selects Q4_K_M. Private Diffusion ships one build of each, retrained after shrinking. The side-by-side on this page shows them in both apps, so you can compare the pictures directly.

  • Atomic Chat ships PostHog and Sentry, and its analytics are on by default with no first-launch prompt. When we captured a first launch, the app sent PostHog an event with a device id, a session id, the OS, the app version, and the screen size about a second after opening, before any click. You can switch analytics off in Settings: PostHog then stops, and the Sentry session reports continue. Private Diffusion has no analytics SDK and collects no data.

Make the Picture, Skip the Pipeline

Every model trained to hold its quality, on the iPhone, iPad, or Mac you already own. There's no account to make, and nothing you create is sent to us.

Pre-order Private Diffusion on the App Store

See how Private Diffusion compares with Draw ThingsSee how Private Diffusion compares with ComfyUI