I guess I'm following up on charles' comment--

-but it doesn't have to be necessarily a bigger picture that the popup displays, right? It could be a whole page with photos and text.

Here's an excellent example of mousovers (not made by me and not with xara either) that show a mini page when the menu is moused over.

http://www.bagborroworsteal.com/ui/howitworks#damage

I like this because there's no click, you just mouse, and it's there. And it might be a great way for the original poster of this thread to incorporate bigger pictures (layout wise I'm talking).

I'm assuming that this exact kind of navigation, showing additional text and photos on mouse movement, is possible with xx4 and the new popup layer navigation feature ( or the rollover with invisible rectangle, but that's more work)