Squoosh

Squoosh is a free, open-source image tool built by the Google Chrome team. It compresses, resizes, and converts images between formats like WebP, AVIF, JPEG, and PNG, with a live side-by-side preview so you can balance quality against file size.

Everything runs locally in your browser, so your images are never uploaded to a server, which makes it fast and privacy-friendly. There is no signup and no limits, making it a great choice for developers and designers who want fine control over image optimization.