Thread:TK10/@comment-22439-20150704035231/@comment-556400-20150704051340

FYI, you can't convert a lossy file type like JPG into a PNG and magically regain fidelity.

Also, as I said in the other topic, you just need to purge the page to force a server refresh, which will load the new image. You purge by adding ?action=purge to the end of the page URL in your browser address bar.