Image Diff Checker
Compare two browser-decoded images, see the changed pixel percentage, and download a red-on-dimmed visual diff.
0 compares exact RGB values; higher values ignore small changes. Images stay in your browser. Nothing is uploaded.
Choose two images to compare.
Images have different dimensions; uncovered pixels count as differences.
Changed pixels are red over a dimmed Image A.
A QUICK WALKTHROUGH
How to use this tool
- Choose two PNG, JPEG, WebP, GIF, or BMP images up to 20 MB each.
- Adjust the RGB Euclidean distance threshold and compare the images.
- Review the red changed-pixel overlay and optional percentage summary, then download the diff PNG.
A visual pixel comparison
The checker compares decoded RGB pixels at matching coordinates. Image A is dimmed beneath a red overlay so changed regions remain easy to spot.
Local processing and limits
Both files are decoded and compared in your browser. Each file is limited to 20 MB and the comparison canvas to 40 megapixels. Different dimensions count uncovered pixels as differences.
GOOD TO KNOW
Common questions
What does the threshold change?
It is the RGB Euclidean distance required for a pixel to count as changed. Use 0 for exact channel comparison.
What happens when dimensions differ?
The comparison uses the larger canvas and treats pixels missing from either image as changed.
Are my images uploaded?
No. Decoding, comparison, preview, and PNG generation happen locally in your browser.