Scumble

Scumble is a free, open-source desktop editor built specifically for AI inpainting. Rather than moving between a masking tool, a generation workflow and a separate image editor, you select part of a picture, say what belongs there, and the result arrives as its own colour-matched layer. It is made for people who inpaint regularly — retouchers, photographers and AI image makers who already work with models such as FLUX 3, GPT Image or Nano Banana and want one place to run and refine those edits. Scumble works with your own ComfyUI instance or your own API keys, so generation stays on infrastructure you already control instead of a subscription service you do not. The project began as a weekend build. Its maker describes doing a lot of inpainting and repeating the same dance every time: build a mask here, run a workflow there, pull everything back into an image editor, fix the edges, and repeat. That loop is the problem Scumble addresses. Each step is individually reasonable, but together they force constant context switching, and the final blending work — matching an AI-generated patch to the lighting and colour of the surrounding photograph — is exactly the part that general-purpose tools handle clumsily. Scumble's answer is to make the inpainting result a first-class layer inside the editor, so the fiddly part of the process happens where you can see it. Selection is deliberately flexible. You can paint a mask by hand, point at an object in the picture, or simply type what it is, letting the editor work out where the selection should be. Whichever route you take, every result comes back as its own layer that is colour-matched to its surroundings, and the original image is never touched. That last detail matters: because the edit lives on a separate layer, an almost-right generation does not overwrite your base photograph. You keep the pixels you started with, and the AI output sits on top as something you can judge, adjust and combine rather than something that permanently replaces your file. Scumble does not lock you into one provider. It runs against your own ComfyUI setup — local, remote or Comfy Cloud — or against your own API keys for a range of models, including FLUX 3, FLUX.2, GPT Image, Nano Banana, Seedream, Qwen and Ideogram. The API path is handled with a privacy detail worth noting: only the area around your selection leaves your machine, and the answer comes back at full resolution. In practice that means you are not uploading the whole photograph to a third-party service just to change one region of it. Because it is your own ComfyUI or your own keys, you pay the model providers directly, and Scumble takes no cut. Prompting goes beyond a single text box. Boxes in the prompt let you draw where things should go and describe each box individually — a capability the maker lists for FLUX 3 Image and Ideogram 4 — so a single generation can place several described objects into specified regions of the frame. Reference images can be addressed by name inside the prompt as well, allowing instructions such as 'put their cup from @img1 on the sill'. Together these two features let you compose edits with a level of spatial and referential control that a plain inpainting prompt cannot express, while still keeping the workflow inside the same editor window rather than spread across multiple applications. Under the hood, Scumble can be driven not only by a person but by an agent. It ships an MCP server with 105 tools, which means Claude Code or any other MCP client can operate the editor directly. Combined with the layer-based output model, that is Scumble's defining approach: inpainting is treated as a normal editing operation that produces a discrete, colour-matched layer, rather than a one-shot generation you have to redo when it is not quite right. The editor also includes 46 film looks that apply as layers, along with retouch tools, so a generated patch can be graded and blended in the same environment it was created in, without exporting to a different application just to finish it. The practical benefit is time. As the maker puts it, colour-matched layers were possible in Photoshop or ComfyUI before, but in a much more cumbersome way; having it directly as a feature in the layer saves a great deal of that time. Commenters on the launch made the same point from the other direction, noting that the layer-based approach makes AI edits feel more like ordinary photo editing instead of forcing a full regeneration of the image. PSD export extends that logic further: if an AI edit is almost right, you can finish it in another editor rather than generating again. Scumble also keeps accounts out of the equation — no account, no telemetry, and API keys stored in the system's credential store. Scumble fits workflows where a photograph needs a targeted change rather than a wholesale reimagining. A retoucher can paint a mask, replace an object and blend the result via a colour-matched layer and one of the 46 film looks before exporting a PSD. A masked region can be regenerated through an API with only the area around the selection leaving the machine, which suits work on images that should not be uploaded in full. Teams building something like virtual try-on, where garment print and texture must stay clean at mask edges, can keep the AI output on its own layer. And with the MCP server, a developer can let an MCP client such as Claude Code drive the editor programmatically. Scumble is aimed at anyone who inpaints often enough to want a dedicated tool: photographers, retouchers and AI image makers already comfortable with ComfyUI or with provider API keys. Integration is broad on the model side — ComfyUI (local, remote or Comfy Cloud) and keys for FLUX 3, FLUX.2, GPT Image, Nano Banana, Seedream, Qwen and Ideogram and more — while output supports PSD, ORA and TIFF export and pictures of 15,000 pixels and more. On pricing it is free and open source under GPL-3.0. Availability is honest about its stage: version 0.1.x and moving fast, with Windows first — a Microsoft Store listing signed by Microsoft, a GitHub installer and a portable zip — Linux builds coming out of CI, Mac planned, and not every API provider tested live. Scumble's value proposition is narrow and clear: it is a free, open-source desktop editor that treats AI inpainting as a layer-based editing task, running on your own ComfyUI or your own API keys. By returning every generation as a colour-matched layer, keeping the original untouched, sending only the selected area when going through an API, and supporting PSD, ORA and TIFF export, it removes the mask-run-edit-fix loop that makes inpainting tedious. Add a 105-tool MCP server and it becomes something an agent can drive too. For anyone who inpaints regularly, it is an attempt to make the process feel like ordinary photo editing.