Responsive site, slider shrinks with size of screen, need help to adjust it.

Ok that is probably a pretty confusing title, but this is what is happening and what I want to do. I have a site and when you shrink the browser window it responds and shrinks the slider as well, which is what it's supposed to do. What I want to do however is make it so that the image doesn't shrink but maybe crops itself. So that there isn't this really big white bar at the bottom.
Hopefully you guys can help. this site if you shrink the window it sort of crops it and has it the whole page. That's what I want to do.