@Joe
Yes I agree that creating a mini/medi/maxi image can be difficult for the average gamer to create therefore downloading one made by pro's is probably the easiest option.
But the original poster (Slon) was actually asking about downloading 'full' images to use as a backup. ;)

Yeah, full images are not really welcome on this forum. ;) However, I wanted to point out, upon mupet0000's question, that, for a newbie, any kind of backup may be difficult to create.