Why do I get the wrong cover art from my iTunes to my iPhone?

I download music from frost wire to my iTunes. On my iTunes it had the correct cover art but when it's on my phone the cover art from songs I've had that are now deleted are on the songs. I downloaded one song by dirt nasty and it gives me the wrong cover art from a song I deleted for ever ago. I even deleted frost wire and iTunes and downloaded them again but the problem still happens Help Please

Unfortunately cover art is typically added to the database by other users or a computer that 'assumes' what you are looking for. I have spent hours updating and adding proper cover art to my albums. You can download album artwork from Google or wherever and add them yourself through iTunes.