Adding album artwork to your iTunes music adds a visual appeal to your music library while also easing the process of finding and identifying your music.
iTunes usually does a good job of automatically adding album art to files as they're imported, but may experience some issues in the event of corrupt or incomplete metadata. Fortunately, there is a simple trick that allows users to manually update the album artwork.
How To Find Missing Album Artworks in iTunes
Open iTunes, click on the Store menu > Sign-in... and sign in with your Apple ID (internet connection required).
Once connected to the iTunes Store, click on File > Library > Get Album Artwork and leave the program to work:
Alternatively, users may also choose to manually upload album artwork. Simply select the items you'd like to edit and go to File > Get Info > Info. Drag an image file to the Artwork area and click OK to save your settings.