shot-scraper is a CLI tool for HTML render snapshots with --height --width and --scale-factor (--retina ~= --scale-factor=2.0) args, and a -j/--javascript option to run JS before taking the screenshot.

There's not yet a way to resize the viewport and take another screenshot without loading the page again.

There's not yet a way to store (h,w,scale,showbrowserchrome) configurations in a YAML file; but shot-scraper does work in GitHub Actions.

Some web testing tools can record a video of a test session and save it if there's a test failure.

E.g. Playwright defaults to an 800x600 viewport for test videos to retain-on-failure or record only if on-first-retry: https://playwright.dev/docs/videos

Something like Cloudflare Browser Isolation - which splits the browser at an interface such that a Chrome browser server runs on a remote server and a Chrome client runs locally - might make it easier to compress recordings of n x test invocations (in isolated browsers or workers)