Graphic overlay to webbrowser

I need a skeleton project in C# from which I'll take the code. The project will consist of a webbrowser object (showing [login to view URL] or any convenient webpage) and a transparent overlay on which graphics may be drawn. There will be a single menu option: "Draw". When Draw is selected, a "smiley face" graphic will be drawn in the centre of the overlay. It is essential that mouse clicks go through to the webbrowser.