Q: Do you know a possible reason why I can’t I see my album artwork in the Cover Flow View on my iTunes library?

– Robert
A: Rather than trying to render album artwork on the fly from within the actual music tracks themselves, iTunes uses a separate artwork cache for Cover Flow view. The most likely cause of missing artwork in Cover Flow view is that the information in this cache has become lost of damaged.
This cache is normally located within your main “iTunes” folder, in a subfolder appropriately-named “Album Artwork,” with two more sub-folders, “Local” and “Download” representing artwork manually added to your iTunes tracks or automatically downloaded by iTunes, respectively:

The “Local” folder is strictly a cache of your existing artwork, and is generated by iTunes from the artwork images embedded within your actual tracks on an as-needed basic. The “Download” folder contains artwork that has been automatically downloaded for your tracks from the iTunes Store. Although this is the only place on your computer that the downloaded artwork resides it can of course always be redownloaded using iTunes’ automatic “Get Album Artwork” feature.
To force a rebuild of the album artwork cache, simply shut down iTunes, and then remove the “Local” folder completely, ensuring that you also empty it from the trash. When you restart iTunes, it should rebuild the “Local” artwork cache as needed. The first time you use the Cover Flow view, it may take some time for all images to properly appear, but once the local artwork cache has been rebuilt, the Cover Flow view should work as expected.