Convert JPG to smaller WebP files — the usual move when you're putting images on a website and want the pages light.
WebP was designed for web pages. All current major browsers display it, and it generally stores a photograph in fewer bytes than JPG at similar visual quality. For anyone running a website, a blog or an online shop, that means lighter pages, faster loading and less data for visitors on mobile plans. It is less useful outside the browser: some desktop programs and upload forms still do not accept it, so keep your JPGs for those.
The JPG is decoded and re-encoded as lossy WebP at the quality you pick: Smaller (62), Recommended (82), High (94), or anywhere from 40 to 100 on the slider. Because the JPG is already compressed, this is a second lossy step, so compare with the original in the preview if fine detail matters. WebP is not automatically smaller in every case. The result list shows each file's old and new size, so you can judge the saving per image rather than taking it on trust.
Encoding happens in your own browser, and not every browser can write WebP. Chrome, Edge and Firefox can. Safari cannot — it quietly produces a PNG instead, and this tool names that file .png so the extension matches what is really inside rather than pretending. If you need real WebP files, use one of the other browsers. Converted files are named after the original with _conv added, and a batch can be downloaded as a single ZIP.
Everything runs inside your browser. Because the image never reaches a server, we cannot store it or look at it. That difference matters when the file is company material or a personal photo.