How do I display thumbnails for subfolders with images in Finder?

Question

Hello. I've settled in quite nicely with OS X but I find there's one thing I couldn't replace with a better alternative from XP and I've looked extensively for a solution but with no luck, so I figured I'd ask.
It's best described with a picture (http://i38.tinypic.com/2j2i1rr.png). All those folders have images in them (at their root, not in subfolders). Instead of the generic folder icon, I'd like a thumbnail of the images in the folder (like this: http://imgsrv.worldstart.com/ct-images/folder-pic-blank1.jpg). The closest I've gotten to this is ticking "Show icon preview" in Finder's view options menu, but this only displays the thumbnails when I actually open the folder which is a bit of a problem when you have 200+ folders and you're looking for a specific one. The only thing remotely like this that I've found is FileBrowse (http://www.filebrowse.com/index.html) but it's too fat and slow to be of much use.
Thanks for any help you might be able to provide.

Answer 1

baltwo: Thanks for the tip, I didn't know how easy it was to set up custom icons in OS X. In this case it's a difficult solution because it will have to be done by hand for every single folder, which is a problem if I'm going to have these in two places. I'm new to Automator but there doesn't seem to be a way to have it; 1) Select all the folders in a directory. 2) Copy the first image in each folder to the clipboard and have it use that image as each folder's icon.
Barney-15E: I know it sounds moronic, but yes. I've tried iPhoto but it's not a very good solution in this case. My folder structure is like this:
Root -> 282 image folders with 10 to 60 pictures in each.
All I really need is the ability to see at a glance what each image folder has without opening each individual folder. The folders are numbered sequentially (1-282 in this case) rather than by proper names, so this is the most efficient way.