Introduction
Parallax is an effect where the background content or image in this case, is moved at a different speed than the foreground content while scrolling. Check out the demo to get a better idea of it.
Open DemoParallax HTML Structure
    <div class="parallax-container">
      <div class="parallax"><img src="images/parallax1.jpg"></div>
    </div>
        Initialization
    $(document).ready(function(){
      $('.parallax').parallax();
    });
        Parallax Customization
The parallax container height is what defines how much of the image can be seen. This is set to a default of 500px. You can add your own style to override this.
    .parallax-container {
      height: "your height here";
    }