Responsive, scrolling images

I'm SURE there is a stupid easy answer to this, but I'm just learning to code and I can't figure out what is going on here.

http://bit.ly/1zuki3W

The images adjust to the screen size, but the page doesn't let you scroll. But the background does move.

So, how do I freeze my background image (that may just be a bounce back in Apples OS?)?

And, how do I get the ability to scroll?