html { background: url(images/bg.jpg) no-repeat center center fixed; -webkit-background-size: cover; -moz-background-size: cover; -o-background-size: cover; background-size: cover; }
body { background-position: center; background-repeat: no-repeat; background-size: cover; }
body { background-position: center; background-repeat: no-repeat; background-size: contain; }
background-position: 10px 20px; /*#10px from left 20px from top*/