Originally posted by: theprodigalrebel
Yup, WMP saves Album Art in the mp3's folder as a hidden file. iTunes embeds the album art into the file itself.
I use MediaMonkey for tagging. Since I'm sort of anal about this, I don't use the in-built feature to fetch album art - I get them manually from Amazon.com, looking for the perfect image. All Album Art HAS to be 500x500 (except for some taller designs) and the colors/contrast has to be just right. The trick with Amazon is to search in the 'MP3 Downloads' section - I've noticed that they are all 500x500 and have exceptional quality. In case I don't find an album available in the MP3 Downloads section, I look at the CD page and go through the Customer Submissions.
After tagging the files, I keep the album art in a backup folder. Sometimes, I use Picasa to generate gigantic picture grids to use as my desktop wallpaper.