The one worth doing by default
WebP beats PNG on size for almost every kind of image, keeps the alpha channel, and has been supported in every major browser since 2020. For anything going on the web this is the conversion that pays, frequently halving the file.
Two caveats. WebP here is lossy by default, so a screenshot of text is better served by the lossless compressor — check the result before shipping it. And Safari has never supported WebP *encoding* from a canvas, so on Safari this page will tell you it has fallen back rather than quietly handing you a PNG with the wrong extension.
Nothing is uploaded
The conversion runs in this tab. There is no upload step, so no queue, no daily limit and no account — and you can disconnect from the network and it still works. The same engine powers theimage converter, which handles any combination and unlimited batches, and theimage compressor, which makes a file smaller without changing its format. Both sit underConverters.