What can *.itc files contain when not PNG or JPG? Yesterday I was a bit curious what iTunes .itc (by default in ~/Music/iTunes/Album Artwork) files were.
After a bit of research, I made a script to convert .itc to images (JPG &amp; PNG).
For 1913 itc files : I get 467 png &amp; 636 jpg files.
I was wondering what the other itc could be. Any idea ?
Well thanks @beroe for the link. 

After some digging I wrote a little documentation of .itc files. 

.itc files are actually wrapper of images that are either PNG, JPG or ARGB raw files. .itc files can hold multiple images with different size. Most of the time there are 3 images of (128*128, 256*256 &amp; 400*400).  

I wrote a little bash script that convert all .itc files into jpg or png and puts them in ~/Music/iTunes/Album Artwork/Images.