Remove all your Thumbs files
You too may have enjoyed Windows and its tendency to hide Thumbs files in any folder containing media files.
Basically, Windows creates those files to let you see thumbnails when you browse from file to file (or folder to folder . . . ).
And as you now run Linux, those files are completely useless for you !
So here is the magic solution to get rid of those parasites :
$ sudo find any_folder -name "Thumbs.db" -exec rm {} \;
any_folder being of course the location you want to sanitize.
You can now enjoy a world (slighlty) cleaner :).