Recently I had put in some new music albums in my ipod and along with that also appeared the artwork (the images that are displayed in background while accessing ipod menu).
There is no suitable option from within the ipod to remove them,however itunes will be helpful in removing the unwanted album artwork.
1.Connect the ipod to computer.
2.Itunes will pop up on screen if installed as soon as it detects ipod connected.
3.Go to Music and uncheck Display album artwork on your ipod option.
4.Disconnect the ipod and check,there should no longer be the album artworks in your ipod.
Peace.