How to keep track of graphic credits?

Hello, all. I stand before you, very humble indeed, a creature who is organizationally-challenged in the worst way. (Probably has something to do with the fact that my mother put away all my socks for me and I never learnt to sort properly...)

Anyway, I download a lot of graphics (e.g., icon bases, templates, borders, brushes, etc.) and I want very much to be able to give credit to the highly talented people who have made them. The problem is I can't figure out a easy, simple system to do so. I mean... when you download a zip file of brushes, how do you mark those brushes so that in future, when you come back and use one weeks later, you know who it was who made them?

Any advice offered would be most gratefully appreciated.

thanks!