# What changed in pixelmatch

> 9 changes in pixelmatch 7 to 8 from its official release notes, upgrade guides and advisories: 1 breaking, 3 new APIs and options. Each one cited. Sources checked 2026-10-18. HTML: https://unstale.sh/npm/pixelmatch/

To see which of these apply to a repository, run `npx @unstale/cli init` in it.

## pixelmatch 8

### Breaking changes

- Color comparison now uses OKLab and HyAB instead of YIQ, changing diff counts to better match perceived color differences. (8.0.0) — [release notes](https://github.com/mapbox/pixelmatch/releases/tag/v8.0.0)

### New APIs and options

- Adds a per-pixel mask for skipping areas such as timestamps or animations. (8.0.0) — [release notes](https://github.com/mapbox/pixelmatch/releases/tag/v8.0.0)
- Returns the largest number of differing pixels in any N×N square instead of the total count, helping distinguish compact changes from scattered noise. (8.0.0) — [release notes](https://github.com/mapbox/pixelmatch/releases/tag/v8.0.0)

### Fixes and other changes

- Anti-aliasing detection is more reliable on images with transparency. (8.0.0) — [release notes](https://github.com/mapbox/pixelmatch/releases/tag/v8.0.0)
- Colors that differ only in transparency are much less likely to be missed. (8.0.0) — [release notes](https://github.com/mapbox/pixelmatch/releases/tag/v8.0.0)

## pixelmatch 7

### New APIs and options

- Controls whether semi-transparent pixels are blended against a checkerboard pattern (true, the default) or plain white (false, the pre-v7 behavior) when comparing images. (7.2.0) — [release notes](https://github.com/mapbox/pixelmatch/releases/tag/v7.2.0)

### Performance

- Performance improves by approximately 8%. (7.1.1) — [release notes](https://github.com/mapbox/pixelmatch/releases/tag/v7.1.1)

### Behavior and default changes

- Antialiasing checks are skipped when includeAA is true. (7.1.1) — [release notes](https://github.com/mapbox/pixelmatch/releases/tag/v7.1.1)

### Fixes and other changes

- Errors on image size mismatch are clearer. (7.1.1) — [release notes](https://github.com/mapbox/pixelmatch/releases/tag/v7.1.1)