Found a small "Hack" for albums with more then one artist.
e.g. the album "Buena Vista Social Club" .. there are many different artist, its a little bit nasty to create for every trak one jpg. so you can cahgne the album name in the ID tags to "Buena Vista Social Club." (spot the dot!

) and then name the JPG "Buena Vista Social Club..jpg" (two dots ).
Its not a beauty sollution. but it works for me

Just wanted to share it with you