PopUp Menu - Linked to Image?

I’m not sure how to create this effect. I have a pop-up menu (really pops down) with a bunch of options that are buttons. What I want is when the mouse is over one of the sub-options I want an image to change to the right of the pop-up. Outside the pop-up, on a different portion of the page. How do I get to this effect from within a pop-up window. I have the pop-up set on the main timeline with on(rollOver) cmds. Any clues??