how to get a menu item that displays a random gallery picture

how can i embed gallery2 so that i can get 1 random picture that changes with every refresh of the page? kinda like the one on the right side of this website. this is for my own website that is being custom built. i want to put this "menu item" at the bottom of every page in the footer where the 6 pictures of leaves are currently located. link to the site is http://dansoft.2x.nu/

sorry about the double post i thought i put the other topic in the wrong section