it is not enough to keep a folder on your computer either, you need to have it backed up somewhere..
I suggest using a 2G thumb drive or even a CD...I prefer the thumb drive as I can take it with me if I need to.
I only keep all that info it is a quilt I designed. For a patterned quilt, a pix is enough. I try to NEVER do the same quilt twice...thus far, the only duplicates I have made were special Memory quilts.