background image css fill screen

1html { 
2  background: url(images/bg.jpg) no-repeat 
3    center center fixed; 
4  -webkit-background-size: cover;
5  -moz-background-size: cover;
6  -o-background-size: cover;
7  background-size: cover;
8}

1body {
2  background-position: center;
3  background-repeat: no-repeat;
4  background-size: cover;
5}

1.Background {
2  background-image: url("Your picture name.jpg");
3  background-repeat: no-repeat;
4  height: 100%;
5  background-position: center;
6  background-size: cover;
7}

1body {
2  background-position: center;
3  background-repeat: no-repeat;
4  background-size: contain;
5}