You have too many high-level folders.
Make a directory structure of folders nested within folders - like this for instance...
ART/PAINTING/MODERN/WARHOL
ART/PAINTING/MODERN/LICHTENSTEIN
It will take time to set up and even more time to file things away in the right place but finding them again will be much quicker.
You just move the contents of each folder - file-by-file
to a more appropriately named and positioned folder.
As your old folders become empty they no longer have any value to you.
Good luck...
Peccavi
January 2013