Do I have a glitch in iTunes? Album Artwork

I have looked through every possible solution for how to add album artwork in iTunes 12 and none of them work for me. I have saved the image to my desktop and tried adding it in the artwork tab within the Get Info window as well as smaller box at the top of the Get Info window and using ctrl+c, crtl+v but none of them work. Each time it will show that the artwork has been added but when I hit OK it doesn't show that it has and deletes the song list, just leaving me with a blank space in my library. The songs don't get physically erased they just don't show up in iTunes until I click somewhere else on the screen.

This used to be easy.