Photo Gallery On Page With Background

I have a page that has a bunch of photos display from that page by using the 'photo display settings' of a thumbnail gallery.  the page template uses a theme template that has a background image.  As you scroll down the page the background image behind the images scrolls too until the end of the background image that then reveals another background image underneath that does not scroll as the page content scrolls down.  I can provide a link to visually see what is happening

Sounds like one of the design elements like this. What's wrong with it?

here is the link. 
as you scroll down you will see the background move until you get past the small thumbnails and then the underneath background remains stationery 

There isn't a link.