Image Pixel Diff

Highlight pixels that differ between two same-size images (heatmap overlay).

Tool Media & Files Updated Apr 19, 2026
How to Use
  1. Drop two images of equal dimensions.
  2. Adjust threshold; red = differing pixels.
Images
A
Drop image A
B
Drop image B
Diff heatmap

Notes

Threshold
Channel delta per pixel
Heatmap
Red = diff, black = same
Overlay
Mixes A with heatmap
Alignment
Pixel-aligned; scale match first
% diff
Count / total
Privacy
Local

About the Image Pixel Diff

The Image Pixel Diff gives you a fast, free answer for image, audio and file tasks without sending anything off your device. Highlight pixels that differ between two same-size images (heatmap overlay).

How it works

Enter what you have and read the result as it updates live. It all runs on your own device, so it is quick and private, with nothing to install.

Want the deeper story? The Knowledge Base explains the ideas behind the tools in more detail.

Frequently Asked Questions

Different sizes?

Both are scaled to match the smaller before diffing.

% diff?

Summary shows differing pixel count.

How do I use the Image Pixel Diff?

Simply type your numbers and read the result, which refreshes the instant you change something. There is nothing to submit and nothing to wait for.

Does it cost anything or need an account?

No. The tool is completely free, there is no account to create, and it keeps working offline after the page first loads.

Is anything I type uploaded?

No. The tool works entirely on your device, so the values you enter never leave your browser.

Common Use Cases

Regression testing

Visual diff across versions.

Compression QA

See where artifacts concentrate.

Last updated: