Album artwork not modifiable

For some reason, some of the songs in my iTunes library won't let me change the album art.. Is there anything I can do about this? Running the newest version of iTunes..

#480301

Use a program that inserts the albumart in the mp3 file for real like mp3tag

A really good app: http://www.mp3tag.de/en/

#480303

Are they protected DRM tracks? Or straight-up no-DRM mp3's?

#480310

No-DRM mp3's

The app above doesn't save changes for some reason..

#480324