ZAMZAR is an online file conversion too allowing you to convert from a selection of files into whatever format is available. Unfortunately it has to send an email when its available. Unlike the other service MediaConnect, you won’t see the results on the same page. I tested out using a High Quality transparent PNG and convert it into JPG. The results weren’t up to my standards and a little bit blurry but it came out fine. It chose black as the background color instead of white though.  Since its in Beta it will take a while for it to be up to my level.