Image Difference Checker
Compare two images pixel by pixel, adjust the tolerance threshold, measure changed pixels, and generate a downloadable difference heatmap.
Upload an original image and a comparison image to generate a pixel-difference heatmap.
Threshold-controlled detection
Ignore tiny encoding changes or lower the threshold to expose every changed channel.
Difference metrics and bounds
See changed pixel count, match percentage, mean error, and the smallest rectangle containing changes.
Downloadable heatmap
Export a high-contrast PNG that highlights changed pixels and dims matching areas.
چگونه کار می کند
- 1
Upload an image pair
Choose the original and comparison versions of the same visual.
- 2
Adjust sensitivity
Set a threshold and amplify the heatmap until meaningful changes are clear.
- 3
Review or download
Read the metrics and save the highlighted difference image.
Interpreting pixel differences
A zero threshold reports every changed RGBA channel. Higher thresholds ignore small variations caused by compression, anti-aliasing, or color conversion. Because the second image is scaled to the first, size or aspect-ratio differences can create broad changes rather than isolated edits.
سوالات متداول
What does the threshold do?
A pixel is marked changed when at least one RGBA channel differs by more than the selected threshold.
Why is most of the image highlighted?
Different dimensions, alignment, compression, or color profiles can change many corresponding pixels.
آیا تصاویر من آپلود می شوند؟
No. Both images stay in your browser.
Image Difference Checker last reviewed: Aug 30, 2026.