it's like shelf liner, sticky on one side and clear and solid on the other. I used to use it to cover my textbooks in school 
Not certain where we're headed here, but you can't print anything on contact/Contac paper.
It comes in rolls of clear, white, and prints. You can cover cake boards with the clear or white. If you cover a board with a print, you need to make certain that the cake doesn't touch it because of the inks in it.
Images printed and applied to cakes are done on frosting sheets with special printers and edible inks. If you have the sheets, you can also paint on them with gel/paste colors. This product is fully edible (an edible image).
In the US, you can get non-copyrighted images printed on edible icing sheets at some grocery stores.
Rae
Perhaps Pookster was thinking of printing an image on regular paper and covering it with contact paper before putting it on the cake. (To keep the paper from absorbing grease and moisture.)
I know I saw a NASCAR cake with stickers on the side, which were covered with contact paper.
Obviously, those would be non-edible decorations. 
Quote by @%username% on %date%
%body%