css set background image to be 100% of screen code example
Example 1: css background image cover
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;
}
Example 2: background: url("image/banner-image-1.jpg") no-repeat center top; background-size:cover;
-moz-backface-visibility: hidden;