iPod Skipping songs.

I have an iPod classic (Latest version) it started to skip certain songs at random points. I have tried resetting iPod, restoring iPod also creating a new iTunes library but nothing seems to work. I have also tried another iPod classic but it happens on the same songs. In iTunes some of my album artwork seems to have disappeared or only half is showing, these seem to be some of the songs that are skipping.

I put the songs onto my iPhone 5 and they work fine, they also work fine on my laptop.If anyone has any advice that would be much appreciated.

Thanks