Outpainting vs Inpainting — When to Use Which (2026)
Inpainting replaces content within a selected area of an image, while outpainting extends the canvas beyond the original boundaries. Both sound similar but serve completely different purposes — and choosing the wrong one adds unnecessary steps to the workflow.
One-Line Definitions
At a Glance: Inpainting keeps image size and ratio unchanged while replacing content within a masked area. Outpainting fills outside the existing image with AI-generated content to expand the canvas. Choosing the right tool upfront eliminates rework and saves significant editing time.
| Feature | How It Works | Output Size Change |
|---|---|---|
| Edit (Inpainting) | AI replaces the masked area inside the image | No change (original size preserved) |
| Expand (Outpainting) | AI fills new content outside the image boundaries | Canvas size increases |
According to Grand View Research, the global AI image generation market is projected to grow at a CAGR of over 17% through 2030, driven in large part by demand for advanced editing capabilities like inpainting and outpainting that go beyond simple prompt-to-image generation.
Edit (Inpainting): When to Change What's Inside
At a Glance: Inpainting regenerates only the masked region while leaving the rest of the image untouched. The overall dimensions and aspect ratio stay exactly the same. This makes it the right choice for outfit swaps, background replacements, and product photo restyling — any situation where the change stays within the existing canvas.
Inpainting works by masking a specific area and having AI regenerate only that region. Everything outside the mask stays unchanged, making it ideal for targeted modifications without affecting the composition.
In XBRUSH, select the Edit tab at the top of the workspace to access inpainting.
Test Case: Casual Outfit → Business Suit
Starting with a portrait of a person wearing a yellow t-shirt and jeans, the clothing area was masked and this prompt was entered:
Prompt: "Transform the casual look into a suit shown from the front, shift to a professional atmosphere"
The result: multiple versions with the outfit changed to a gray suit and tie, while pose, background, and facial appearance remained identical to the original. No reshoot required — a direct application for e-commerce product styling and fashion lookbooks.
When to Use Inpainting
- Outfit or prop swap — Change clothing style, color, accessories, or footwear
- Background replacement — Keep the subject, replace the setting entirely
- Product photo restyling — Swap props, tableware, or background atmosphere
- Face and expression editing — Adjust hairstyle, expression, or specific facial features
The rule: Use inpainting when the image dimensions stay the same and only the content changes.
For a step-by-step walkthrough of inpainting applied to product photography, see the inpainting guide.
Expand (Outpainting): When to Extend the Canvas
At a Glance: Outpainting fills the area outside the original image with AI-generated content that matches the existing atmosphere, lighting, and style. It is the correct tool for aspect ratio conversion, adding text margins, and standardizing multiple images to the same canvas dimensions. XBRUSH uses the Qwen Image Edit engine for outpainting.
Outpainting preserves the original image and generates new content around it to expand the canvas. The original pixels are never modified — only the surrounding area is filled in.
In XBRUSH, select the Expand tab at the top of the workspace to access outpainting.
Test Case: Portrait Photo → Square Composition
A portrait photo taken at a café terrace was uploaded. After selecting the expansion direction and target size, multiple versions were generated with the canvas expanded outward. The final result converted the portrait ratio to a square composition, with the café atmosphere naturally extending into the new area.
When to Use Outpainting
- Aspect ratio conversion — Portrait to landscape, square to 16:9
- Adding margins — Create blank space for text or logo overlay
- Standardizing sizes — Fit multiple differently-sized images to the same canvas
- Ad creative resizing — Adapt one image to multiple platform specs
The rule: Use outpainting when the goal is to increase canvas size or change the aspect ratio.
Full documentation for the Expand feature is available in the outpainting & background removal guide.
How the Two Technologies Work Differently
At a Glance: Inpainting analyzes the pixel context around the masked area to generate replacement content that blends seamlessly. Outpainting reads the boundary pixels of the original image — color, texture, perspective — and generates matching content outward. Both require a high-quality AI model to produce coherent results, which is why engine selection matters.
How inpainting works: The masked area is cleared, and the AI model analyzes surrounding pixel color, texture, and semantic context to fill the void. XBRUSH's Edit function uses the nano-banana-pro and Seadream 4.5 engines.
How outpainting works: Starting from the boundary pixels of the original image, the AI infers perspective, lighting, and color temperature to generate content that continues naturally outward. XBRUSH's Expand function uses the Qwen Image Edit engine.
According to NVIDIA's research on diffusion model architectures, context-aware inpainting models achieve significantly higher coherence scores when the mask area covers less than 40% of the total image surface — keeping masked regions focused and specific produces the most accurate results.
Decision Guide
At a Glance: If the goal is to change image size or aspect ratio, use outpainting. If the goal is to change part of the image content while keeping the same dimensions, use inpainting. For complete background removal, use the Background Removal tool. For resolution enhancement, use Upscale.
| Goal | Tool | Why |
|---|---|---|
| Change image size or aspect ratio | Expand (Outpainting) | Extends canvas in selected direction |
| Replace part of the image content | Edit (Inpainting) | Replaces masked area, preserves the rest |
| Remove background entirely | Background Removal | Isolates subject with transparent background |
| Sharpen a low-resolution image | Upscale | Enhances resolution and restores detail |
| Add text or layout elements | Canvas Editor | Layer editor for text and image compositing |
| Swap outfit or props only | Edit (Inpainting) | Keeps subject and background, changes target area |
| Resize for multiple platform specs | Expand (Outpainting) | Converts one image to Instagram 1:1, YouTube 16:9, etc. |
A Powerful Three-Step Combination
At a Glance: The most effective workflow combines outpainting first (to set the canvas size), inpainting second (to refine the content), and background removal last (to isolate the subject). Order matters: outpainting applied after inpainting can inadvertently undo edits at the boundary.
The two features are most powerful when used together in sequence:
- Use Expand to set the target canvas size and aspect ratio
- Use Edit to refine content within the expanded canvas
- Use Background Removal to finish with a transparent background if needed
Practical example: a portrait product photo needs to become a landscape banner. First, Expand converts the portrait to a 16:9 canvas. If the expanded background area looks inconsistent, Edit is used to blend the boundary. Finally, Background Removal isolates the product on a clean transparent layer ready for compositing.
For more on the layer editor and compositing workflow, see the layer editor guide.
Real-World Use Cases
At a Glance: Inpainting and outpainting deliver measurable cost savings across e-commerce, content creation, and game development. According to Statista, 62% of e-commerce companies that adopted AI image editing tools reported reducing product photography costs by 40% or more.
E-commerce and Online Retail
- Seasonal background swaps without reshooting → Inpainting
- Convert portrait product shots to banner landscape format → Outpainting
- Isolate product and place on various backgrounds → Background Removal + Inpainting
Social Media and Content Creators
- Convert square Instagram photos to YouTube thumbnail 16:9 → Outpainting
- Add text margins to existing images → Outpainting
- Create multiple outfit variations from a single photo → Inpainting
Game Developers and Illustrators
- Generate character costume variations → Inpainting
- Extend background artwork to multiple resolutions → Outpainting
- Adjust sprite canvas dimensions for game engine requirements → Outpainting
For a complete guide to using XBRUSH for game asset production, see how to create game sprites with AI.
Prompt Writing for Inpainting and Outpainting
At a Glance: Effective prompts for inpainting describe only the target area — not the full image. Outpainting prompts describe the atmosphere and continuation style desired for the new area. In both cases, shorter and more specific prompts tend to outperform long, complex instructions.
The quality of inpainting and outpainting results depends not just on the tool but on how the prompt is written. The two techniques require different prompting approaches.
Prompting for Inpainting (Edit)
Inpainting prompts should focus exclusively on what the masked area should become. Avoid describing the parts of the image outside the mask — the AI preserves those automatically. The clearer and more specific the target description, the more accurate the replacement.
- ❌ Weak: "Change the image to look professional"
- ✅ Strong: "Gray wool suit with a white dress shirt and navy tie, front view, professional atmosphere"
- ❌ Weak: "Make the background nice"
- ✅ Strong: "Bright modern office interior, natural light from the left, soft bokeh background"
Prompting for Outpainting (Expand)
Outpainting prompts should describe the visual atmosphere, lighting conditions, and style that the new area should continue from the original. Matching the original image's mood and color temperature produces the most seamless extensions.
- ❌ Weak: "Extend the background"
- ✅ Strong: "Continue the outdoor café setting, afternoon sunlight, same warm color temperature as the original"
- ❌ Weak: "Add more space on the left"
- ✅ Strong: "Extend the studio white background, even lighting, minimal shadows, consistent with the right side"
For a detailed guide to prompt writing across all XBRUSH features, see the prompt engineering guide for AI images.
Common Mistakes and How to Avoid Them
At a Glance: The most common inpainting mistake is masking too large an area — keeping the mask under 40% of the image produces significantly more coherent results. The most common outpainting mistake is expanding too far in a single step — incremental expansion in smaller increments produces more natural results than one large jump.
Inpainting Mistakes
| Mistake | What Happens | Fix |
|---|---|---|
| Masking more than 40% of the image | AI loses contextual reference, result looks inconsistent with surrounding areas | Break large edits into smaller masked sections; edit in passes |
| Vague prompts ("make it better") | Unpredictable results; AI interprets broadly | Describe specifically what the area should contain |
| Masking areas with complex lighting | New content has inconsistent lighting with the rest of the image | Include lighting direction in the prompt; use smaller masks near light sources |
Outpainting Mistakes
| Mistake | What Happens | Fix |
|---|---|---|
| Expanding the canvas 50%+ in one step | Sharp visual discontinuity at the boundary | Expand 20–30% at a time; regenerate multiple steps |
| Leaving the prompt blank | AI guesses the continuation; results vary widely | Always describe the desired atmosphere and continuation style |
| Expanding in an unnatural direction | New area has no logical connection to the original | Consider the physical space in the original; expand only in directions that make visual sense |
Frequently Asked Questions
What is inpainting?
Inpainting is a technique where a specific area of an image is masked and AI regenerates only that region. The overall size and ratio of the image are maintained, and everything outside the mask stays exactly as it was in the original. Common uses include outfit swaps, background changes, and prop styling.
What is outpainting?
Outpainting is a technique that fills the area outside the boundaries of an existing image with AI-generated content to extend the canvas. The original image is never modified — new content is added around it. Common uses include converting portrait photos to landscape format and adding text margins to existing images.
Should I use inpainting or outpainting to change a background?
Use inpainting (Edit) to replace a background. Inpainting changes the inside of the image, so the subject stays intact while only the background is replaced. Outpainting extends the canvas outward and is not designed for background replacement within the existing frame.
Can inpainting and outpainting be used together in XBRUSH?
Yes, both can be used in sequence and work well together. The recommended order is outpainting first to establish the target canvas size, then inpainting to refine the content within the expanded area. Combining both with Background Removal produces the most polished results.
Can inpainting change a face or a person?
Yes. Masking the face or person area and entering the desired change as a prompt allows targeted modifications to expression, hairstyle, outfit, or other features. For precise results, the mask should be drawn carefully around the specific area to be changed rather than covering a broad region.
What should I do if the outpainting result looks unnatural at the edges?
If the expanded area does not blend smoothly with the original image, try expanding in smaller increments over multiple steps rather than in one large extension. Gradual expansion gives the AI model more context to match the existing atmosphere. Any remaining inconsistencies at the boundary can be addressed with a follow-up inpainting pass.
Related Articles
- Inpainting for product photos
- Creating banners with canvas layout
- Prompt engineering guide for AI images
Tools Used
- XBRUSH Edit (Inpainting) — Replace content inside an image (nano-banana-pro, Seadream 4.5 engine)
- XBRUSH Expand (Outpainting) — Extend the image canvas (Qwen Image Edit engine)
- XBRUSH Background Removal — Remove backgrounds and generate transparent PNG
- XBRUSH Upscale — Enhance image resolution and restore detail
Last updated: 2026-04-15 · Written by Byoul Oh, Content Lead at XBRUSH