Image Compare / Diff Tool

About this tool

Compares two images two ways: a slider to visually drag between them (great for before/after edits or design revisions), and a pixel-level diff that highlights exactly which pixels changed, with a percentage-different score. Everything runs locally in your browser — nothing is uploaded anywhere.

If the two images are different sizes, Image B is scaled to match Image A's dimensions for comparison — this is most meaningful when comparing two versions of essentially the same image or screenshot.

Frequently asked questions

What counts as a "different" pixel in the diff view?

Any pixel whose color differs from the corresponding pixel in the other image by more than a small tolerance (to avoid flagging harmless compression noise as a difference) is highlighted in red on a dimmed grayscale version of Image A.

Why does resizing Image B affect the diff result?

Pixel diffing compares images pixel-for-pixel at the same coordinates, so both images must be the same size — if they started at different sizes, this necessarily distorts B's proportions slightly, which can itself register as differences.

Is either image uploaded anywhere?

No — both the slider and the pixel diff are rendered entirely in your browser.