i have creative zen vision m. and the album art feature of the player, and other creative players, ABSOLUTELY SUCKS. it is really annoying. i used to have the same problem: one album art for all albums on the player. one way to fix this is to delete all songs, download media monkey, add album art to your tracks using media monkey and then transfer your music to your player with wmp or zen explorer or any other program.
Make sure to be consistent with what program you use to transfer cuz switching between programs, can also cause problems (as it did for me).
yes this is really hectic, especially if you have many songs. what you could also do is try to use an auto tagging prog. iv tried a few, however they dont change tags/arts once a song has already been transfered.
i would also recommend not having any album art at all. to do this, make sure no song has album art before you transfer.
oh this is a really common problem.
have fun messing around.