Diff Highlight
Generate a composite image where pixels that differ between the two images are highlighted in a vibrant colour. Adjust tolerance to ignore compression artefacts.
Click or drag image here
PNG, JPG, WebP, GIF
Click or drag image here
PNG, JPG, WebP, GIF
How Diff Highlight Works
For each pixel at position (x, y) the tool computes the Euclidean colour distance between the two images in sRGB space. If this distance exceeds the tolerance threshold, the pixel is painted in the chosen highlight colour in the output image. Pixels within the tolerance are copied from Image A unchanged (or dimmed, if "Dim unchanged" is checked).
When the two images have different dimensions, only the overlapping region is compared. The output image will be sized to this common area.
Choosing the Right Tolerance
Tolerance 0
Any difference - including JPEG compression artefacts or sub-pixel rendering variations - is highlighted. Best for comparing losslessly encoded PNGs.
Tolerance 3-10
Recommended for most use cases. Ignores minor encoding noise and anti-aliasing differences while highlighting structural and colour changes.
Tolerance 15-30
Only large colour or luminance changes register. Useful when comparing heavily compressed images or screenshots from different operating systems.