The thumbs.db file caches photo thumbnails in a directory for quick viewing when you browse that particular folder. I always like to turn this feature off since I often mirror directories across FTP servers that contain many photos. The thumbs.db is needless bandwidth and also plays with the synchronization settings. Be aware that turning this feature off does slow photo thumbnail viewing within folders.
To turn this feature off:
- Control Panel -> Folder Options -> View -> “Do not cache thumbnails”
- Search for “thumbs.db” in your drive and delete all thumbs.db files from the search window.