.jumbotronW
{
  
    background: transparent !important;
}
.jumbotronExtra
{
    
     margin-top:100px;
  margin-bottom:100px;
}
.bg {
  /* The image used */
  background-image:url("back.jpg");

  /* Full height */
  height: 100%;

  /* Center and scale the image nicely */
  background-position: center;
  background-repeat:no-repeat
  background-size: cover;
    
    
}