I've just released Mp3tag v2.52!
With this version it's now possible to specify a default directory that is used when adding cover art. This was a long-requested feature, especially after the changes introduced with Mp3tag v2.51.
Furthermore, this version fixes minor issues that have been reported after the last release of Mp3tag. For a full list of changes please see the History of Changes.
You can download the new version from
http://mp3tag.de/en/download.html
Enjoy 
Kind regards
Florian