Upgrading iTunes Artwork


I want to upgrade the quality of some of the cd artwork in my iTunes library but I cannot delete the old artwork without deleting all of the music tracks as well. How do I delete the existing artwork (not the music) so I can import (click and drag) better quality artwork in.
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Sidssp: Thank you! I just now did "upgrade" one bit of artwork but am struggling with the second one. . it just doesn't want to change! I'll get it - you have me on the right track!! I'm following your input on the other thread as well. Your explanation is good - I'll respond over there as it develops. Thanks again.
Sidssp: OK! I got it - your advice was perfect. Now I will be up all night upgrading iTunes artwork - your fault!
in iTunes I select all the songs on the album needing a new or different artwork. I highlight the artwork window. Then I open my web browser, go to google images and search for the cover I need. I search for the best, then I copy the image to the clip board. I return to iTune. I paste it into the artwork frame I had previously highlighted. I can't paste the picture with the mouse but I can with edit command menu. I had to learn this because iTune doesn't like some of my older MFSL cd's or it just can't located any artwork.
I search for the image I want, then download it into My Pictures first. I have Google Toolbar installed with the Picture widget, cycling through My Pictures. So I get a random slide show of all the covers I have downloaded - kind of cool.

After that, it's pretty much what's posted above. I use Download from iTunes first, as it's the fastest way and the image is not stored inside the file. But in many cases, iTunes does not give me the Cover I want. So I have to replace it.

There are three different ways to get the artwork in there. Choose the one you like.

Just be sure it's applied to all tracks - not just the first one of the album. Highlight the track and ensure a picture displays on lower left - use the down arrow to work through all the tracks and check.

Regards,