OK, It finally makes sense to me. I must confess, I don't know of a way to do this, but what I would recommend is that you grab Windows Live essentials, and in particular the Photo Gallery:
http://explore.live.com/windows-live-photo-gallery
It's a brilliant (not to mention free) addition to Windows 7 that allows you to organize your pictures, tag them, and sort them in all kinds of ways. Much better than browsing through the actual folders, and by default it shows you a thumbnail view.