Actually I would consider me to be a rather experienced Windows user (although I prefer Linux ;) nevertheless it took me until today to gather myself and solve the mystery of those tedious thumbs.db files which tend to show up whenever some pictures are around in a directory.

As suspected Windows uses the thumbs.db files to speed up the creation of the preview pictures when accessed again. Although the thumbs-files are hidden one can’t help to stumble over them from time to time. And that is becoming increasingly annoying.

To get rid of them you hust have to deactivate the caching of those miniature previews in Extras -> Folder Properties inside Windows-Explorer options by placinga mark at do not cache miniture previews (might be called something else, I only have a German Windows installed, sorry). Now there should be tidiness again.
Already created thumbs.db files are beeing deleted when a picture within the same folder as the thumbs.db file is opened with the Windows Picture- and Faxviewer.