dsh-screenshot-diff

In visual regression workflows, screenshot capture and pixel comparison are often bundled, but you may already have two rendered images and simply need to see exactly where they differ. dsh-screenshot-diff does one thing: it pixel-diffs two existing images. It captures nothing—you supply the two files.

It produces two outputs: a diff.png with changed pixels highlighted in red, and a labeled triptych compare-triple.png showing A, B, and the diff side by side. Sensitivity comes in three presets—normal, high, and ultra—ranging from stable to extremely sensitive, with an explicit --threshold override for finer control. A size mismatch between the two images triggers an immediate failure rather than a silent stretch, so layout regressions are never masked. A JSON summary (similarity, numDiffPixels, total, sensitivity, threshold) is written to stdout for downstream automation.

Ideal for developers debugging UI changes, teams building visual regression pipelines, or CI jobs comparing two build artifacts. A practical tip: start with the normal preset, verify the diff lands where you expect, and only escalate to high or ultra when you need to catch subtle gradient or anti-aliasing shifts.