I believe that JPEG is the best format for making a good photo, whereas PNG is better overall for any other kind of image. The OS actually supports a huge vari

I believe that JPEG is the best format for making a good photo, whereas PNG is better overall for any other kind of image. The OS actually supports a huge variety of images natively, including PNG, JPEG, TIFF, GIF, several Windows formats and X-Windows bitmaps. PNG is definitely the smallest and fastest to render, especially when compiled by Xcode (Apple does some hacking to the file format so that the device doesn't have to do as many calculations at runtime).