You can change the icon for the folder, but you're probably going to end up changing the icon for all folders if you do change it.
Open the desktop folder.
-Click the File Types tab
-Click the Advanced button near the bottom of the dialog.
-Click the file type you want to change the icon for
-Click the Change Icon button near the top of the next dialog.
-Choose your icon.
**Fair warning - I changed the icon for a file type once, and had a lot of trouble getting it back to normal.