Manually adding Artwork (like from iTS)

Question

Hi there, I'm scanning the artwork that comes from my CDs to add them to the songs. I'm noticing that when I do it, the song file size grows. Which sounds logical. At the same time I understand that what happens to the song-files when the artworks are downloaded automatically from the iTS is different (I'm not sure here, I'm just guessing): The songs don't really grow in size as the artwork doesn't really go into them. What I understand is that they are stored somewhere else and the songs just refer to them.
If this is true, well, I see an obvious advantage, the songs stay the same size and probably it's faster to play them and display their artworks.
If there's any expert around in the iTunes ways, please help me out. If the way iTS downloads and adds the artworks into the songs is better, and there is a way to replicate it, I'd love to know how. Otherwise I'll stick to my fully manual process.
Thanks.

Answer 1

I artwork already is embedded in the song files, iTunes won't get artwork from the iTunes store.
You could delete all artwork and then get the ones from the iTunes Store, but this is a bit tricky. If the artist or album isn't available at the Store, no artwork is downloaded. So you end with nothing for those albums.
I would consider getting assistance from a script to save the existing artwork first.
The first one which came in mind is Save Album Art to Album Folder.
It saves the artwork from the selected tracks to the folder where the song file resides or to a chosen folder. But it saves the artwork of all tracks, not just the album.
Another, more attractive option is to save the artwork using Export Artwork to iPhoto.
This one has an option to save only one piece of artwork of an album.
After you saved the artwork, select all tracks (Command-A) and 'Get Info' (Command-I). Check the checkbox at 'Artwork' and click OK.
iTunes will remove all embedded artwork.
Select all tracks again and choose 'Get Album Artwork' from the Advanced menu. Alternatively control-click on the selection and choose 'Get Album Artwork' from the contextual menu.
After a while, iTunes will have downloaded the artwork for (hopefully) most albums. You then can add missing ones from your iPhoto library.
Which method you choose, it will take a lot of time depending on the size of your library.
Ideal would be a script that saves the artwork, deletes it from the song file, requests the Store for artwork, deletes the saved artwork if artwork is downloaded or adds the saved artwork if no artwork is downloaded.
However, such a script does not exist (yet) as far as I know.
Some notes:
You must be using iTunes 7.0.x
You must have an iTunes Store account.
The song, artist and album names must exactly match the ones at the iTunes Store, although recent experiences showed to me that minor mismatches still will download the correct artwork.
M
17' iMac 800 MHz, 768 MB RAM, 200 GB HD, DL burner   Mac OS X (10.4.8)   iTunes 7.0.2