You make a small program similar to Paint (minus all the Paint options and features) that only allows you to draw on a surface (probably a Picturebox). Your program supplies the drawing surface, drawing pen, and a way to erase (perhaps some other features as well to do other things you feel is necessary) . I believe there are sample programs in the Code Bank that address this drawing program. If you can make such a program then I see no reason why you couldn't embed that into a chat-like app. The code for sending and receiving the pictures would be practically the same as that of a normal chat program. Many chat programs have the ability to send/receive images so your program wouldn't be much different from those.