The way I have done it is to use the Mouse Move event. Stack the two pictures one on top of the other. Make the one that is going to pop up when you move the mouse over it invisible. Then in the Mouse Move event of the visible picture, make the current picture invisible and the invisible one visible. Then to turn it off again put in code to do the opposite in the Mouse Move event of the Detail section.
I have done this in some of the switch boards I modified. It will 'highlight' the selection by changing the color of the font for the menu option. However it is possible to move out of the detail section before the Mouse Move event is run. You have to move the mouse pretty quickly or catch the computer running another process. It's not perfect but adds a little to the form.