background-image: url(path-to-file/img.jpg);
background-repeat:no-repeat;
background-position: center center;
That should work.
If not, why not make a div with the image and use z-index to make it the background? This would be much easier to center than a background image on the body.
Other than that try:
background-position: 0 100px;/*use a pixel value that will center it*/ Or I think you can use 50% if you have set your body min-height to 100%.
body{
background-repeat:no-repeat;
background-position: center center;
background-image:url(../images/images2.jpg);
color:#FFF;
font-family:Arial, Helvetica, sans-serif;
min-height:100%;
}
I use this code, it works nice
html, body {
height: 100%;
width: 100%;
padding: 0;
margin: 0;
background: black url(back2.png) center center no-repeat;;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
}