iTunes Artwork Location

Where does itunes store its artwork?

I've copied an album cover into itunes and its low res, now when I try to replace it the original low res one just remains.

Can I actually just copy over the actual file its reading? or are these hidden?

Thanks

Ricky55

By default it saves in Music-iTunes-Album Art then there is two different files there which contain the data, however its in a .itc format. Doe's it not work if you play a track from the album then drag the high res images in to the box that appears in the bottom left?

Highlght the track/album in question and hit Command + I.
Drag the new artwork to the box labeled as such.
Hit 'OK' and it should replace the old artwork.

If it is only for a track, highlight it and do the Command + I.
Click on the Artwork tab and you should see what is there. If you have two items, highlight and remove the one you don't want.

thanks