Simon Willison released shot-scraper 1.12, adding WebP output to the command-line screenshot tool, according to his release notes. A new --quality flag sets lossy compression, as in shot-scraper https://simonwillison.net -o screenshot.webp --quality 80; omitting the flag produces a lossless WebP file.
Willison said WebP screenshots are "almost always significantly smaller in file size" than equivalent JPEG or PNG output, based on his own testing.
He built the release while producing screenshots for commit-rewriter, another small tool he shipped the same week to help edit AI-agent-generated commit messages before they go public.
Shot-scraper is widely used for automated documentation and CI screenshot pipelines, so a lossless-by-default format that runs smaller cuts storage and bandwidth for anyone running it at scale, with no change to an existing workflow beyond the file extension.