JPG to WebP

WebP compresses photographs about a third better than JPG does at the same apparent quality. If you are putting images on a website, that is a straight saving with no visible cost. If you are sending a file to somebody, JPG is still the safer choice.

This is a re-encode, so it is worth being clear about generational loss: the JPG already discarded detail, and WebP now discards a little more from what is left. In practice this is invisible at sensible quality settings, but it does mean you should convert from the highest-quality original you have rather than from a file that has already been through several rounds. If you still have the camera original or the export from your editor, start there.