make huge photo fit perfectly in background css code example

Example 1: how to set background automatically with my screen height

html { 
  background: url(image.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;