Artwork disappeared on phone

Hi,

So I plugged in my phone one day to my pc to download some pictures from my camera and after I had synced them and unplugged my iPhone all of my music artwork disappeared but the artwork shows up on my pc so I tried syncing multiple times see if my phone can get the artwork that is supposibly there and I can't get it back how do I fix this? Also my music gets cut off, like the song isn't all there but plays fine when I use the iTunes on my pc what can I do to fix that