command for background cover image code example
Example 1: CSS make image fill whole background
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: how to set background image 100 height
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;
}