I knew that there has to be some other folders that keeps album arts. If anyone has the same problem of changing album covers in N900 you just need to: $ rm ~/.cache/tracker/file-* $ rm ~/.cache/media-art/* $ rm -R ~/MyDocs/your-music-folders/.mediaartlocal (this I think is optional but it's safe to do this) $ tracker-processes -r Restart device (in my case)... Have a nice album-arts.