Image Diff

How to use

1. Add the reference image

   Upload the baseline or golden image that you want to trust as the source of truth.

2. Add the comparison image

   Upload the screenshot or export to verify. Different dimensions are automatically scaled to the reference.

3. Adjust tolerance and read the diff

   Move the tolerance slider to ignore compression noise. Review the magenta overlay and the reported match percentage.

Scope of the result

Two image files, each up to 50 MiB, and only MIME types beginning with image/. If their dimensions differ, the second image is stretched to the first one's size before comparison, so a different aspect ratio makes the whole frame read as changed. The result is shown on screen only; there is no diff image to download. Files are not uploaded.

Frequently asked questions

Are my images uploaded to a server?

No. All processing happens directly in your browser. Files never leave your device, and nothing is stored on any server.

What image formats are supported?

Any format your browser can open: JPEG, PNG, WebP, GIF, BMP, SVG, AVIF, and more. The diff is drawn on a canvas for quick inspection.

How are transparency and alpha handled?

Pixels that are fully transparent in both images are treated as matching, regardless of their RGB values. Otherwise, alpha differences are counted in the diff.

How should I pick a tolerance value?

Use 0% for cryptographic checks, 1–5% for compressed exports, and higher values when comparing screenshots with anti-aliasing or font rendering differences.