For use with iTunes, you can extract the artwork from the selected track’s ID3 tag and copy it to an image file in a chosen location. It is also a fully fledged artwork manager as it can fetch album covers from all over the internet!
Export Artwork – 4.1.10 – (Shareware) – PowerPC friendly – Leopard 10.5 – http://mac.brothersoft.com/export-artwork.html
Export Artwork – 4.1.7 – (Shareware) – PowerPC friendly – Tiger 10.4