Merge Images
Merge two images online by painting which parts to keep from each. Detected differences seed the mask; refine with a brush, then download. Free, with no upload.
Files never leave your browser.
About Image Merge
Composes a final image from two source images using a mask painter. Paint regions to take from the left or right side. Built on top of Image diff so detected differences seed the initial mask.
How to use
- Pick a left and right image of the same dimensions.
- Detected diff regions seed the initial mask; refine with the brush or eraser at the size you need.
- Download the merged result as a PNG when you're happy with the mask.
What this tool doesn't handle
- Mismatched dimensions are handled by scaling the smaller image (enable auto-scale, fine-tune in the alignment workspace), but resampling can add minor noise. Identically sized exports compare most precisely.
- Mask editing is destructive; only the latest stroke can be reversed via the eraser.
Frequently asked questions
Do my files ever leave my browser?
No. Every comparison runs locally in your browser. Nothing you paste, drop, or load is uploaded to a server; the tool keeps working even if you go offline after the page loads.
Is this tool free to use?
Yes. All DiffResolver tools are free, with no account, sign-up, or installation. Because processing happens on your device, there are no server-imposed usage limits.
How do I choose which parts of each image to keep?
Paint the mask: regions assigned to the left take pixels from the left image, the rest from the right. Detected differences seed the initial mask, and you refine it with the brush or fill bucket.
What format is the merged image saved in?
PNG by default, which is lossless, so no quality is lost from either source. Use the format selector next to Download if you need a different output format.
Is there a file size limit?
No server limit applies, because nothing is uploaded. The memory of your device sets the practical limit. Above 10 MB for text, 40 MB for images, 100 MB for documents, or 500 MB for archives, the tool warns you that the work can be slow, but it never blocks the file.
Does this tool work offline?
Yes. The browser keeps a copy of the tool after the first visit, so a page you opened before still works without a network. You can also install DiffResolver as an app from the browser menu. Installation stays optional; the site works the same in a normal tab.
Where is my data stored?
Your files are stored nowhere. They stay in the memory of the page and are gone when you close the tab. Only what you save yourself stays in this browser: a snapshot, your tool options, and your theme. To remove it, open Settings and select Clear all local data.