The scoop on itunes artwork

I just got off the phone with Applecare, asking a bunch of questions about managing artwork. For those interested, I though I'd post the answers here. Any additional knowledge to add, feel free. Here is a log of my Q/A:

I have a large library, with many missing artwork(s). I've been manually adding artwork for each album, by having the artwork display on (located lower left in itunes), going through my library album by album, and for each album where artwork doesn't show up, dragging a google album cover image into the artwork display area. I should note that my library has a variety of song formats: aiff, alac, mpeg, mp3, wav. Here are my questions:

Q1 - Is this an appropriate method?

A1 - Yes. Better to update artwork on the album level than the song level, so this is appropriate. Another way to associate artwork on the album level is to highlight all album songs, go into “get info”, and add the artwork there. This is more cumbersome and adds no advantage to the method described above.

Q2 - where does the new artwork actually reside with this method? I looked at my "artwork" folder within my "itunes" folder, and its “modified” date was long ago. That makes me think the artwork is being stored somewhere else. Can you tell me specifically where artwork is stored? Might the storage method vary for music files of different format, or processed differently within itunes (e.g. purchased from the store, artwork added automatically during CD ripping, artwork added manually later)

A2 - Music that comes from the apple store is in the album artwork folder, other sources are stored in the library itself or the library xml. The Apple advisor says he thinks that itunes no longer embeds artwork into songs. Beyond the source distinction (itunes store vs. other), the method of storing artwork does not vary with the format of the song file. I asked about wav files, which do not seem to support linking to a graphic file, and he had not heard of that problem.

Q3 - If I assign artwork to just one track, does Itunes assign it to the whole album, or do I need to select the entire album to make this happen? This is a lot of work, so I want to do it right the first time.

A3 - If you select a song and go to “get info”, you can associate an image to just to that song. If you just associate with a song, the rest of the songs on the album will not have associated artwork.

Q4 – Can you advise me on how to properly back things up so that I don't ever have to do this again. For this, I need to understand how itunes associates artwork for a given song. Does it associate artwork entirely within the library (i.e. does the library link song tags to artwork in the itunes artwork folder: so if you lost your library, you'd be in real trouble)? Or, does itunes associate artwork to the tag in each song (i.e. when I add artwork, is each song tag modified with specific artwork information, or with the artwork itself)? I back up my whole music folder (1.3 tb), and my library stuff. Should I be backing up my artwork folder too? Do all these three items need to be backed up to maintain the artwork? If I had to rebuild my library from scratch, is there a way I’d be able to retain the artwork associations?

A4 - When you add artwork, it does not affect the song tag. As noted above, the artwork remains either in the artwork folder (for purchased music) or embedded in the library and library.xml files. He recommends that you back up your entire itunes folder rather than individual files within it, along with your itunes music (mine is separate, so I copy my itunes folder onto my external music hard drive, and then back up that entire hard drive). I asked about the “old libraries” folder and he explained that this is created when you switch (upgrade) versions of itunes. Itunes saves the old library associated with the old version. You can delete the “old libraries” folder without harm.

Q5 – Are there ways to make the management of artwork more secure and invulnerable to future disruptions. I know there are scripts that do things such as embed artwork into song tracks or add an artwork file to each folder, so that each folder contains a jpg with the cover art. (BTW - The Squeezebox system requires one of these two options to "see" artwork, though it does have a new experimental feature to extract artwork from itunes, a friend of mine has not had success with it). If I did this, would my data storage be more invulnerable to losing either the itunes library file or the itunes artwork folder? Is this a wise “insurance” step?

The only way to gain security is to keep a good backup of your entire backup folder along with your itunes music folder (even if it’s in a separate location).

Hope that is helpful. Peter S.