Renaming an image "Folder" in my music

Hi everyone!

I have been updating my winamp thumbnail database with all the associated album art.

Every so often, I run into a little problem.

When I add a new image to a band's folder and rename the image "folder.jpg" I get an error message stating that I "cannot rename the file because there is already another with the same title" or something along those lines.

This typically happens with albums I have previously added album art through with my "Zune" (mp3 player).

I have tried "showing hidden files and folders" but the image seems non-existent.

Is it stored in a thumbnail cache somewhere? Can I delete some temporary icons? any help?