I have been making audio files via CDs and first using professional encoding software incorporating the LAME process before converting into 320 bit rate mp3s and now I simply use iTunes make all of the audio files into the m4a audio format, which will replace the AIFF/wav format before too long. It is full fidelity and half the file size. So I have had a need to edit and add to the information that I get from the CDDB.
To do this, you need a "tagging" tool. To do it manually with just your Finder and iTunes, you are NOT changing the audio file, merely the information on your Mac, or heaven forbid a PeeCee. When you move, save JUST the audio files away from that Mac, those audio files DO NOT have that extra/edited information.
That includes the images! You need to use a tool that will actually enter the audio file and embed the data into the audio file, actually alterring the audio file and increasing the audio file size. If you want the image to FOREVER stay with the audio file, you have to embed that file. So a program that saves an image for the entire album to keep the file size down is not touching the audio files.
It might be nice for some purposes to keep the image files away from the audio file it goes to for file size reduction, but not when you are making a forever, one-time digital audio archive. FetchArt is storing the images away from the actual audio files.
Now let me tell you about my personal collection that I am working on. First of all, all of the audio files are of the m4a format! This means the average song is 28 to 34 MBs each!!! Figure ONE GIG for each three music albums imported. Folks, I ain't playing around and I have well over 1 TBs of m4a files now, over 60,000 songs!
Now do you want to use FetchArt to forever embed all of those audio files? No, especially since FetchArt is not embedding the audio, but rather it is saving the images on your hard drive.
Use FetchArt for a few albums. First take note of the file size of each of the songs. Then use FetchArt and go back to look at the file size again. If it is the same, the images cannot be in the audio file!
What is why I do not use FetchArt! Plus it seems to crash alot.
In fact, I do not use just one product to do all of my tagging, I use two shareware products. Free is nice, but you usually only get what you pay for!
The number one tagger for all audio files is Media Rage if you are using a Mac! This gets most all of your tagging needs done, as well as tagging your images. It is relatively fast, but how fast is it when you are still doing some of the manvuering for each album manually? Remember I have 60,000 audio files all needing an image to be forever embedded in it. It is $29.00 and worth every penny.
So if you have thousands and thousands of audio files all needing an image, there is only ONE choice to start with. It is MPFreaker.
MPFreaker will take a folder of audio files and will go out to Amazon and get the correct image for most all of the songs in that folder. It does have problems with most all double and more CDs, box sets and such. But it rarely will screw up and get the wrong image and I have given it a folder with 3860 audio files and it got about 85% of those done in about 90 minutes! Try doing that with anything else! It would take many hours any other way.
As for the other 15% of the audio files that are left untagged with an image from MPFreaker, I use Media Rage to get those done. MPFreaker is $20.00. http://www.lairware.com/mpfreaker/
So there you are, iffin you're playing around with a few thousand files, use what you want to use. But iffin you looking to make a real audiophile digital archive that's real visual, you gotta use the correct tools to do it!
Then once you have all of your audio files tagged with images, you should give some of the 3rd party iTunes visualizers a try, like JewelCase http://www.opticalalchemy.com/products.html and Cover Version http://www.imagomat.de/coverversion/ a try, or for a super treat get the only 3rd party iTunes visualizer worth buying, G-Force. http://www.soundspectrum.com/ Then connect your Mac to your home entertainment system and get blown away!!! I have always had a Mac connected to my big screen and sound system since the first day I ever used one at home!