@media all and (orientation:portrait) {
   body {
  
    background:url("http://kenmishima.com/toobig/imgs/background-portrait.jpg") no-repeat center center fixed;
    -webkit-background-size:cover;
    -moz-background-size:cover;
    -o-background-size:cover;
    background-size:cover;
}
}
@media all and (orientation:landscape) {

body {

    background:url("http://kenmishima.com/toobig/imgs/background-landscape.jpg") no-repeat center center fixed;
    -webkit-background-size:cover;
    -moz-background-size:cover;
    -o-background-size:cover;
    background-size:cover;
   
}
}