<!DOCTYPE HTML>
<html>
<head>
<style>
#image {
  position:fixed;
  opacity:0.50196078431;
  left:0;
  top:0;
  width:100%;
  height:100%;
  background:blue;
}
</style>
</head>
<body>
  <div id="image"></div>
</body>
</html>