Deleting album artwork

I have attempted to delete the album artwork for a song I find offensive (the artwork, not the song - "Blurred Lines," if you're wondering). In iTunes, I right clicked on the song, Get Info, Artwork, then selected and deleted the artwork. This seemed to be successful, but after I sync to my phone, the offensive artwork is still displaying on the phone itself when iTunes is running in landscape orientation (when the display switches to a 5x3 mosaic of album art tiles). How do I fix this?