Since I got Windows 7, one thing that really sucked was I couldnt view the image previews (or thumbnails) in the folder view. After searching the internet, i eventually foudn a solution. It so easy, I wish i knew how to fix it before.
All you hvae to do is go to TOOLS->FOLDER OPTIONS->VIEW. Now uncheck “Always show icons, never thumbnails”. Thats about it. Click apply, and Okay. You now have thumbnails of all images. Good luck!