About this tool
Compare two images pixel by pixel: highlighted difference map, changed-pixel count, SSIM similarity and PSNR — all in your browser.
If the sizes differ, the second image is scaled to the first. Pixels whose largest channel difference exceeds the tolerance are marked in the highlight colour over a faded copy. Similarity uses the mean SSIM of 8 × 8 luminance windows; PSNR comes from the mean squared error.
Example: two screenshots of the same page before and after a CSS change show the moved button in pink and 0.8 % different pixels.
Heavily compressed JPGs differ slightly everywhere; raise the tolerance to ignore compression noise.
Quick steps
- Choose your files — they stay on your device.
- Set the options and check the preview or the test results.
- Download the result. Your original files are never changed.
Files are processed in your browser and are not uploaded to 1CLIK.
FAQ
How does the Image Compare (difference & similarity) work?
If the sizes differ, the second image is scaled to the first. Pixels whose largest channel difference exceeds the tolerance are marked in the highlight colour over a faded copy. Similarity uses the mean SSIM of 8 × 8 luminance windows; PSNR comes from the mean squared error.
What should I keep in mind?
Heavily compressed JPGs differ slightly everywhere; raise the tolerance to ignore compression noise.
Are my files uploaded?
No. Everything happens on your device; nothing is deleted or overwritten, and results are new downloads.