Childrens colouring in project

I am looking to install a facility on a web site that will allow a user to color in the picture on the page like in a childrens colouring in book. The entry page will look like the blank page of a childrens colouring in book with an outlined blank drawing. The page would have some kind of color palette available. The user should be able to pick a color and drop that color in to a particular area of that line drawing. The colored in picture must be printable Please see [login to view URL] for a good idea about what is required