This works how you want it.
It stretches the image vertically and positions it in the center.
body {
margin:0px;
background-color: #525252;
}
#background {
width: 100%;
height: 100%;
position: fixed;
background: url('bk.jpg') center / auto 100% no-repeat;
}
Alternatively, if you want support for older browsers, see this jsFiddle solution. It uses the img
tag as opposed to setting the image via background-image
.