context-sensitive image menu?

Is it possible to have a menu consisting of image buttons that shows a different image for the selected menu that corresponds to the site navigation? In other words, if you click on a menu button that says About, it will take me to the About page, and the menu button will show a different image indicating that you are currently at the About page.

What's the best way to implement this in drupal? I'm using the bluemarine theme. Thanks!