If you want to add or change picture of of mp3 songs or you want change artist or album name in mp3 songs than use mp3tag software
download mp3tag (FREE)
just drag your mp3 song to mp3tag software and change artist album name left side
you can add comment to mp3 songs not only comment you can add composer name, year and Genre
for adding movie poster or your picture to mp3 song than right click on left side squre box as shown in figure
1st remove old piture than add new one.