a span {
  display: none;
  text-decoration: none;
  }

a {position: relative;
   text-decoration: none;
   }
 
a:hover span {
  position: absolute;
  top: -5px;
  left: 100px;
  display: block;
  z-index: 100;
  width: 200px;
  background-image: url(http://www.raphaelpooser.com/pix/cvtooltipbg.png);
  border: 1px solid orange;
  }