Scumble

A free, open-source desktop editor for AI inpainting. Select part of a picture, describe what should be there, and the result comes back as an editable layer, colour-matched to its surroundings. Scumble renders with FLUX 3 Image, FLUX.2, GPT Image, Nano Banana, Seedream, Qwen Image Edit and more through your own API key, or locally on your own ComfyUI, and keeps the work in layers you can export to PSD. Manual, videos and the dev blog: denrakeiw.com/scumble.

Work in progress. Scumble is in an early state (0.1.x). Not every feature has been tested end to end yet. Expect rough edges, keep backups of your images, and please report what breaks in the issues.

How it works: open an image, select an area (brush, shape, magic wand, object hover or a text description), write a prompt, generate. The result lands as a layer over the selection and can be blended in with colour match, erased in parts, regenerated, stacked with filter and text layers, and exported with all layers to PSD or OpenRaster. Or open the assistant and say what you want: it drives the same editor through the same commands an external agent gets, one card per step, and asks before anything costs money.

Watch: Scumble, explained by someone who did not ask (4:40): two voices, one sceptic, the whole app recorded in the app.

Rendering happens on your own ComfyUI (local or remote, for example on RunPod) or through API providers: Google (Nano Banana 2 / 2 Lite / Pro), OpenAI (GPT Image 2.5 Flare / Sunburst, 2), Black Forest Labs (FLUX 3 Image, FLUX.2 max / pro / flex / klein, FLUX.1 Fill), ByteDance Seedream 5 and 4.5, Qwen Image Edit and Qwen Image 2.1, Ideogram 4.5 (edits with the selection as its mask), and on Magnific its own Mystic, Ideogram mask inpainting and Image Expand outpainting (FLUX Pro, Ideogram, Seedream 4.5), each through the model's own API where Scumble has one (for Seedream that is ByteDance's BytePlus ModelArk) or through ToAPIs, fal.ai, Replicate, WaveSpeedAI, Comfy Cloud, Comfy Router, OpenRouter, Oxen.ai and Magnific. Object masks and background removal run inside the app through ONNX Runtime (SAM2, BiRefNet, RMBG). The editor is the same code as the ComfyUI node Inpaint Canvas; Scumble is the standalone window around it, plus recipes, plugins, an MCP server and the assistant.

Windows first (from the Microsoft Store or the installer below), a Linux build (AppImage, .deb) that has not been tried on Linux yet, macOS is planned. Free software, GPL-3.0. What has been verified so far: local rendering through ComfyUI, the in-app helper models, the film pack, the command core, the MCP server, the tile engine on large documents and auto-update, and among the API providers FLUX 3 Image on Black Forest Labs (with boxes in the prompt), OpenRouter and Comfy Router, GPT Image 2.5 through OpenRouter, and Ideogram 4 on fal.ai (with boxes); the other API providers and the assistant's model calls are untested against the live services.

Features

Select, prompt, generate

Paint a selection (or draw a rectangle, an ellipse, a lasso, use the magic wand, hover an object, or type "the handbag" for a text selection), write the prompt in the Generate tab, press Generate. The recipe decides where it runs: your ComfyUI, or a provider with a key.

• Selection by brush, rectangle, ellipse, lasso, magic wand, object hover (SAM2 in-app) or by text (SAM3 on the ComfyUI side); grow, shrink, feather, invert, from layer, saved selections.
• Recipes instead of node graphs: pick a model ("FLUX.2 [max]", "Nano Banana 2") and the provider it runs on (ToAPIs, its own API such as BytePlus ModelArk for Seedream, fal.ai, Replicate, WaveSpeedAI, Comfy Cloud, Comfy Router, OpenRouter, Oxen.ai, Magnific); import your own ComfyUI workflow as a recipe if it holds an Inpaint Canvas node, or a copy of a shipped model recipe with a variant of your own. Thirteen of Comfy's templates come as Comfy Cloud recipes: image edits (Boogu, Flux.2 Klein 9B, Flux.2 dev, Mage Flow, Qwen Image 2.1 and 2509) and new images for Generate new (Anima, Flux.2 Klein 9B, Ideogram 4, Krea 2 Turbo, Mage Flow, Qwen Image 2.1, Z-Image Turbo); a workflow from Comfy Cloud becomes one as it is.
• API runs go out at the size the provider really takes (Highres fix picks the tier), with reference layers, and transparent results from the OpenAI image models land as cut-outs.
• Start from nothing: Generate new makes the base image from the prompt alone, locally or through a provider, and you edit it from there.
• Boxes in the prompt for FLUX 3 Image and Ideogram 4 (on fal): draw boxes on the picture with the Boxes tool (X) and say what each one does (add something new, keep, move or remove an element, place a reference layer, render words); the run tells the model where each change goes. With no boxes drawn, the selection goes as one box. One switch under the prompt turns them on and off, and the boxes are saved with the document. Ideogram 4 gets them as its structured caption (new things, words and kept elements; it has no move, remove or reference boxes).
• Prompt upsampling through a stored API key, an OpenRouter, Oxen.ai or ToAPIs key, or a local Ollama / LM Studio, with your own prompt-writing rules as Markdown templates.

Layers, filters, text

Every result is a layer. Match its colours to what is below it, mask it, erase parts, set a blend mode, put filter layers and text on top. Nothing is baked in until you flatten.

• A full layer stack: paint, image, text and filter layers, masks, blend modes, opacity, retouch tools (clone, heal, smudge), transform, crop and extend, copy and paste of whole layers between tabs, SVG files as layers.
• Colour match per layer: a result that came back a shade off is matched to its surroundings (or to what lies below it) with one slider in the layer row, non-destructively; the slider can also stay at 40 % when the model's own tone is worth keeping.

• Filter layers on the GPU (WebGL2): grain with film presets, curves, levels, colour balance, HSL, LUT (.cube), vignette, normalise, sharpen, blur and more; a film pack plugin with film looks, halation, glow, bleach bypass, cross processing, split toning, light leaks, frames and control points.
• A shape tool (rectangle, ellipse, polygon, Bezier, freehand path, fill and outline), custom brushes from Photoshop .abr files, and 3D objects (.glb) placed into the picture with their own light.
• Export PNG, JPEG, WebP, PSD and ORA with layers, masks and selections, at a percentage or in a frame of a given size; an AI label panel writes the EU AI label into the file.

The assistant

A chat column next to the canvas. It runs on your own API key, on Anthropic, OpenAI, Google or any OpenAI-compatible endpoint (OpenRouter, DeepSeek, Moonshot / Kimi, Z.ai / GLM, ToAPIs, WaveSpeed, Oxen.ai, or a local server), and drives the editor through the same 90+ commands an external MCP client gets. Every call is a card you can open; everything that costs money, queues on your ComfyUI, clears the undo stack or touches a layer that is not its own asks first.

• Ctrl+Z takes back each of its steps, and Undo this turn puts every document the turn touched back to what it was before, even when the turn was longer than the undo stack.
• Chats are saved as they go, with their screenshots, and can be reopened; Settings > Assistant deletes everything the assistant ever stored, your keys excepted.
• Your own model ids: Settings > Language models takes any model of any listed provider (an OpenRouter id, a model released after this version) for the assistant, for prompt upsampling, or both, on the key that provider already has.
• The whole feature, what leaves your machine per provider and what it costs: docs/ASSISTANT.md.

Large pictures, plugins, agents

• A tile engine keeps the picture, every layer and every mask in tiles; the pixel kernels run as compiled Rust in workers, so a 15,000 x 10,000 document paints, saves, selects and exports without freezing the window, and PNGs beyond the canvas limit (up to 65,535 px a side, a gigapixel) open and save in strips.
• JavaScript plugins (filters with CPU and WebGL2 paths, panels, menu actions, tools, commands) and a command core with 96 documented commands (79 core, 17 from the built-in plugins) (docs/COMMANDS.md).
• MCP server: Claude Code, Claude Desktop or any MCP client can drive the editor (Help > Copy MCP registration puts the line for your client on