desktop.ini - A hidden file located in Windows folders that saves viewing options for that specific folder. This file can specify an image that is used for the folder icon as well as appearance options for files within the folder. It can be ignored, but if you delete the desktop.ini file, Windows may generate a new one. Mac OS X .DS_STORE files serve a similar purpose.
I use to have this problem when I was playing MP3 music in Windows Media Player for Windows Vista & Windows 7 And then Windows 8, when I played music in Windows Media Player this album art always showed up in the music and would neve go away, I mean I re tagged all my music, deleted the comments, composers, disc numbers, only tagged artists, album info, year, genre, removed the album arts, cause some people just don't add the details to the MP3 correctly, I use Mp3tag for tagging music and removing those annoying comments that says "By some dude who uploaded music please visit my site" blah blah blah anyway.
This is an example of the annoying album art it always showed up even playing any MP3 file on my desktop, I had to format my PC 3 times I thought formating my PC would get rid of this annoying this but sadly it was still the same.
Then I did lots of Google Search until I found out I had to go to Folder Options and uncheck "Show hidden files and folder drives" "Hide Empty Drives in the computer folder" "Hide protected operating system files (Recommened)" Once I unchecked those then it showed up all the art, desktop.ini, some desktop hidden file here are more snapshots.
Once I deleted all of those then when I played my MP3 music it finally worked the album artwork was gone for good :D
So why does this stuff appear hidden in files?