I gave those out as gifts for the girl's who attended my son's party last year. They were plastic with the pictures outlined in metal and you used paint to fill in the picture. Kind of like paint by numbers. The metal out-line held the paint in place. Then let it dry.
Sounds close - these are completely made by the child.
You put plastic over the pictures provided, follow the lines with black glue then fill in the voids with color. Let dry overnight and then peel and stick.