If you happens, like me, make a lot of graphics, and want to save a lot of space, I recommend JPEGmini. It compresses Jpegs to a fraction of the original size without any visible quality loss. I bought the full version and by doing that I can convert a folder. My compressed folder today was 20 Mb before and after compressing it was just 4.7 Mb. That means about 16 Mb smaller! Nice!