Around our login area, we place a div with the following class:
sourcecoast facebook login jfbclogin
We've seen some templates in the past that have a CSS declaration for 'facebook' and it shows that image. Since that's for a large area encompassing our login module, it will show many of those images as the background.
I just tried to load your page a lot and couldn't see the repeated images, but hopefully that explanation helps you look through your template (or module) CSS files to see if any of them have a generic 'facebook' style with an image background. If so, try to disable that CSS.
I hope that helps,
Alex