This was a "nice" add-on with PhotoShop 7 which became a true "feature" in PhotoShop CS with the ability to enlarge previews to a reasonable size without a loss in image quality (even without using "generate high-quality previews - see below).
So I'm flush in a world of cheap storage and my 80GB laptop drive makes me feel "crowded". But ok, I have my external drive (a HUGE plus for the recent global reinstall), DVD backups, and so on.
When I reinstalled Adobe CS and got back to work on my current job, I found the file browser... slow? Not quite the right word. Stuck? More like trudging through molasses trying to generate previews, even after I installed the latest RAW update.
OK, check PhotoShop's RAM allocation, delete preferences, yada yada... Turns out the Application Support folder for File Browser contained over 1.25GB of previews!!! Gawd! I guess I had ticked "generate high quality previews" at some point, and I was still dragging some of them around with me all this time.
Wiped the entire folder (~/Library/Application Support/File Browser/PhotoShop CS). The File Browser is happy as a clam and I recovered some valuable disk space.
Normally when I need to "clean house", I search for large files, say those over 500MB, then over 100MB, etc. Usually after the second pass I've got >10% free space and I stop. But this folder had a whole bunch (2000+) of files none larger than 30 or 40 MB. I guess I need to come up with a better housekeeping system.
C.