I'm using this Galleriffic image gallery in a website I'm building: http://www.twospy.com/galleriffic/example-2.html

I want to be able to click on the large image(not the thumbnails), and it goes to a full screen image, a bit like a lightbox type of effect. Can anyone tell me how easy/difficult it might be to acheive this? My jquery knowledge is virtually non-existent, but my css is ok.