I had the problem of music album artwork being completely wrong - not matching the song being played. I had this with iOS 6 on my iPod Touch 5. I got no help from Apple Tech support and infact a great deal of being ignored. But I did find a post on this forum that solved the problem. Tech support should read the posts - they might understand the user complaints. This post was by 'Edl4304', to whom I am very grateful, and the link to it was https://discussions.apple.com/thread/3801919?answerId=21201891022#21201891022. Just in case you can't find it or its no longer there - this is the heart of the post...
Step-by-Step Procedure:
1. Back up your iPhone to your PC using iTunes.
2. On your PC, download and install iFunBox, a free utility that will allow you to access the
system files on your iDevice; (try www.i-funbox.com)
3. On your iPhone, go to Settings\General\Usage\Storage\Music and swipe and delete All
Music. (I'm not sure this is necessary, but it worked for me.)
4. Turn off your iPhone, then restart it.
5. Put your iPhone in Airplane mode so it will not be disturbed while syncing.
6. Make sure iTunes is not set to start automatically when a device is connected and close it on
your PC if open.
7. Run iFunBox and connect your iPhone via cable to your PC. Look for the "iFunBox Classic"
tab and click on it.
8. Connect your iPhone via cable to your PC.
9. Your device will appear under "Connected Devices" in iFunBox.
10. Navigate to the file, "MediaLibrary.sqlitedb" in folder "Raw File
System>iTunes_Control>iTunes."
11. Rename, "MediaLibrary.sqlitedb" to, "MediaLibrary.sqlitedb.backup." (Note: Do not
rename or delete, "MediaLibrary.sqlitedb-shm" or, "MediaLibrary.sqlitedb-wal." Neither of these
are the file you're after!)
12. When done, eject / dismount your iDevice from iFunBox, then disconnect the cable.
13. Close iFunBox. Reboot your device again by turning power off and back on. (Again, may
not be necessary, but after spending weeks trying to get this problem fixed, I figured another two
minutes wouldn't hurt.)
14. Start iTunes on your PC and reconnect your device to the sync cable.
15. Sync your device. When done, be sure to eject / dismount your iPhone from iTunes before
disconnecting the cable.
16. Take your phone out of Airplane mode.
17. Check to see that your album artwork has returned.