Can’t add album artwork

im having a problem with iTunes completing it sync with iPhone. It stalls at 7 of seven tryin to sync with artwork. I assume it’s album artwork?

when I review the file of artwork can’t be updated I go to the song get info the add artwork is greyed out, and I can’t manually add. The others in the album have the artwork associated with them, and the file has the same permissions as the others. Why won’t itunes update these, or let me manually do it