gniusBackground resizes the image in full-screen with aspec ratio depended on its browsers window size. It also has options to be scrollable or fixed.
Just add this Code below in each section.
###Javascript:
new gniusBackground('myElement',{
scrollable : false,
width : 894,
height : 894
});
###HTML:
<div id="myElement">
<img src="yourImageHere" />
</div>
###CSS:
#myElement{
top : 50%;
left : 50%;
z-index : 1;
}