By default, whenever you pick “thumbnail” or “tiles” view, in your Windows Explorer, a local cache of a pictures thumbnail will be stored in that directory, in a file called Thumbs.db. It speeds things up next time you open that directory, because it can load the image from the cache – but it also creates an extra file in every directory …
This can be annoying when you’re used to publishing things through SVN, or when uploading several directories. The silly Thumbs.db will be uploaded as well.
You can disable it by going to Tools > Folder Options and checking the option “do not cache thumbnails".
Do not cache thumbnails
When you select “Apply to all folders", not a single folder on your PC will create that file. If the file already existed, it’ll still be there – so you should still manually delete those. (Start a search in your “My Computer” for “Thumbs.db”, select them all and hit the delete button)