Solved

I've removed the offending drop-down menu, and replaced it with a pop-up window containing a list of all the pictures on the site. When you choose a picture, the pop-up closes, and the picture is displayed in the original window - fantastic!

You can also access this list from any page using the 'all pictures' link in the left hand menu.

Still not sure if I like the pop-up window, but we'll see how it goes. When there are more names in the list, the window will be scrollable. Let me know if you have any suggestions.

Dan