missing album covers

I plugged my iPhone into my computer today. i didn't intend for it to sync since i had it on a setting that it doesn't sync when its connected. Now that it synced all my album covers are messed up. Some are not where they should, some aren't showing up at all. When i go to iTunes on my computer all of the albums covers are in the right place and everything is fine. I tried re-syncing, restarting my phone and computer nothing changes it. SOMEONE PLEASE HELP. I add songs and added my own covers and this took hours. any help is welcome