Why serve WebP instead of JPG
Images are usually the heaviest thing on a web page, and WebP attacks that directly: at comparable visual quality, WebP files typically come out 25-35% smaller than their JPG equivalents. Lighter images mean faster Largest Contentful Paint, better Core Web Vitals scores, and less bandwidth spent by your visitors — all of which search engines and users notice. Browser support stopped being a concern years ago; every current browser, including Safari, renders WebP without fallbacks.
What actually happens to your file
When you add a JPG, a Web Worker decodes it and re-encodes the pixels using the browser's built-in WebP encoder, running on a background thread so the page stays responsive. Because no library has to be fetched and no server is involved, conversion is quick even for large photos. Each result shows the original size next to the new one, so you can verify the savings file by file rather than taking the 25-35% figure on faith.
Converting a whole image folder
Site migrations rarely involve one image. Queue everything at once — three files convert in parallel while the rest wait their turn — and export the results individually or as a single ZIP ready to drop into your assets directory. All of this happens inside the page you're looking at: your photos and product shots are never uploaded, logged, or stored anywhere, because the conversion has no server component at all. There's no account to create, no watermarking, and no daily quota, so you can run an entire site's image library through it in one sitting.