I'm using CS6 in Windows 7 64 (bit) - I've successfully used File Types Manager (freeware) to change file type icons (since the Windows file type editing has been removed). My problem is that JPEG, PNG, & GIF change in lockstep - (like you would expect all of a similar type - ex. JPG, JPEG, etc. to do). BMP and TIFF are not affected. Is anyone familiar with this? Is it a Windows or Photoshop matter? (This was not a problem in Windows XP and CS.) I would just like to have the correct icon (provided in the Photoshop.exe file) associated with the various file types. I know, that may be too much to ask.
As an alternate thought, this won't directly give you what you want, but it might actually be something even better...
Have you considered getting a codec pack that will show you thumbnails of the actual photos instead of icons? There are some packages for free and some that are inexpensive.
Windows Explorer view, set to Extra Large Thumbnails:
Photoshop File - Open view, set to Large Thumbnails:
Note that even raw files are interpreted into thumbnails.
Also, Windows Photo Viewer becomes functional on all these file types.