jest-image-snapshot

What jest-image-snapshot is

jest-image-snapshot is a free, open-source Jest matcher for image comparison in visual regression testing. It stores a baseline image on the first run and compares later test images against that reference. Comparisons can use Pixelmatch pixel checking or structural similarity, with SSIM described as experimental. Users can set per-pixel sensitivity and an overall failure threshold by pixel count or percentage. Configurable Gaussian blur helps address noise from images scaled at different resolutions. The matcher can create horizontal or vertical diff layouts and optionally print a base64 diff or an iTerm inline image in the console. Installation uses npm, and the listed Jest peer dependency range is versions 20 through 29; versions below 20 are unsupported. Browser screenshots can serve as test inputs, while an example reporter uploads failed diffs to AWS S3 for ephemeral CI environments. Baselines can be refreshed with Jest’s --updateSnapshot or -u option. The package is self-hosted, has no cross-browser capture, and its TypeScript definitions are community maintained rather than officially supported.