body { 
background: url('http://www.ronjatpoggioli.com/9FIC_0166-home2.jpg') no-repeat center center fixed;
-moz-background-size: cover;
-webkit-background-size: cover;
-o-background-size: cover;
background-size: cover;
} 
.transparent
{
 opacity: 0.6; /*  CSS3  */
   filter(opacity=60);  /*  Pour IE  */
}