Album Artwork

So I have this album I bought back in 2005 (in-store). I love this album and have been playing it a lot recently. I've also been revamping the artwork for my songs if I don't see any there which makes for a much more colorful iTunes experience, which I enjoy! But no matter what I try (like deleting the artwork I tried adding first, then trying a smaller file... deleting the cache album artwork file... anything) nothing works to make the artwork I add to iTunes also appear on my phone. It shows up on my desktop just fine, I just don't understand why it isn't doing the same on my phone after I sync it.... Anyone know what I can try next? Thanks!