Download and install Mp3tag. Mp3tag software is a freeware utility for editing catalog information on digital media such as ID3, MP4 and WMA data. Catalog information, or "tags," includes song title, artist, album, production notes and album art.
Run Mp3tag software by selecting the program from your start menu, desktop shortcut or running the executable file from the install folder you selected during installation. Select "File" then "Change Directory" and use the dialog that opens up to navigate to the folder where you store your digital music. The right side of the screen displays the directory and existing catalog and file format information of your music collection in list form.
Use your Internet browser to navigate to Discogs, an online music release catalog. Input the artist and album title into the provided search field. Select the album on which the song you wish to add album artwork to appears from the search results. Click on the album art and save it to your desktop by right-clicking on the image and selecting "Save As."
In the Mp3tag software right-click on the image of a disk beneath the "Discnumber" field on the left side of the screen. Select "Add Cover" from the drop-down menu. Navigate to your desktop in the dialog screen and select the album art you downloaded from Discogs.
Save the art to the MP3 by selecting "File" then "Save Tag." The software automatically embeds the art into the MP3 file and the image you selected will show up in media players when the song is playing. Since the art is now embedded into the file, you may delete the image file you downloaded from Discogs.