What girsempa said above is absolutely right AFAICT. Sounds like he knows what he's talking about. :-D The one advantage JPEG gives you (IMO, AFAICT, etc) is that it allows you a lot of control over the file size. That's important for things you want to put on the internet if you don't want people on a slow connection to wait for the image to load for ages. But as long as you just want to save a copy for your own future use TIF or RAW should be your friends. :-) If you want to look into the details, I think some wikipedia articles are actually pretty good, if you ignore the technical and mathematical stuff (which always make my head spin).