Hmmm, one picture per album works, if each file contain only one picture (Mp3tag v2.37d).
Well, for other cases, I don't know.
I think that the cover area of Mp3Tag needs a litle bit more brain grease, it is not well formed yet.
Running an action like this from above against files which have 4 pictures embedded there was following result:
Robby Ameen.Afro-Cuban Grooves for Bass and Drums.jpg
Robby Ameen(1).jpg
Robby Ameen(2).jpg
Robby Ameen(3).jpg
Only the first file is proper named.
The following files are numbered as expected, but let missing the %ALBUM% field.
DD.20070124.2033