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Inpainting, Outpainting, and Generative Fill: A Practical AI Image Editing Workflow

How to use inpainting, outpainting, and generative fill together to edit and extend images with AI tools, with a workflow you can copy.

Lumen AI Editorial6 min readEdit this article
Before and after image edit showing generative fill extending a background

Generation from a blank prompt gets most of the attention, but the more useful everyday skill for AI image tools is editing an existing photo: removing an object, extending a background, or swapping a detail without redoing the whole shot. That's the job of inpainting, outpainting, and generative fill.

The Three Techniques, Defined

Inpainting replaces a selected region inside an existing image — removing a person from a photo, fixing a blemish, or swapping an object. Outpainting extends an image beyond its original borders, generating new content that matches the existing scene, useful for changing aspect ratios. Generative fill is the commercial term Adobe popularized, essentially a polished combination of both, integrated directly into a familiar layer-based editor.

Editor using a mask tool on an image
Masking the region you want to change is the first step in inpainting.

A Repeatable Editing Workflow

  1. Start with the highest-resolution source image available; upscaling after editing produces worse results than starting high
  2. Mask precisely — a sloppy mask edge is the most common cause of a visible seam
  3. Write a targeted prompt describing only the replaced region, not the whole image
  4. Generate multiple variants and select rather than accepting the first result
  5. Blend edges manually with a soft brush or feathered mask if a seam is visible
  6. Export at full resolution and check under zoom before delivering client work
Layered image editing interface
Layer-based control keeps edits reversible.

Tool Comparison

ToolBest forIntegration
Photoshop Generative FillProfessional retouching with full layer controlNative to Creative Cloud
RunwayVideo-adjacent editing, object removal in footageStandalone app
Stable Diffusion (via ComfyUI or similar)Maximum control, open-source, freeSteeper learning curve
Canva Magic EditFast consumer-grade editsBrowser-based, minimal setup

Photoshop remains the default for professional retouching because it keeps generative edits inside a non-destructive layer stack, so a bad generation doesn't cost you the original file. For teams that need it embedded in a broader creative suite, see our notes on Canva Magic Studio.

Visualization of a generative model filling in missing pixels
Generative fill predicts plausible pixels for the masked area.

Common Failure Modes

Generative fill struggles most with edges that involve fine detail continuity — hair against a busy background, reflections, and text that continues across the masked boundary. It also occasionally introduces subtle lighting mismatches that are easy to miss on a laptop screen but obvious in print. Always review edits at full size before final delivery, and for anything with legible text nearby, cross-check against the accuracy issues we cover in our Ideogram text rendering review.

Commercial Use Considerations

Because inpainting and generative fill modify real photographs rather than creating wholly synthetic images, the legal picture is somewhat different from pure text-to-image generation — the underlying photo's rights still apply, plus whatever terms the AI tool attaches to the generated portion. We break this down further in our AI image copyright guide.

Team reviewing an edited product photo
Commercial teams increasingly rely on generative fill for product photography.

Where This Fits Into a Broader Design Stack

Inpainting tools rarely replace a full design workflow; they slot into one. Product photography teams use generative fill to swap backgrounds for e-commerce listings without a reshoot. Marketing teams use outpainting to reformat a single hero image into every social aspect ratio. Browse our full AI image and design tools coverage for adjacent tools worth pairing with an editing workflow.

Bottom Line

Inpainting, outpainting, and generative fill are the most immediately useful AI image capabilities for anyone doing real production work, because they save reshoots and manual retouching hours rather than replacing creative direction. Learn to mask precisely and write targeted regional prompts, and the tools will save real time on nearly every image-heavy project.

#inpainting#outpainting#generative-fill#photo-editing