<!doctype html>
<html>
<head>
<style>
:root {
background-color: #418BCA;
background-repeat: no-repeat;
background-size: cover;
background-image: url("http://bonurtek.com/wp-content/uploads/2014/05/gradient-wallpaper-1.jpg");
height: 100%;
}
:root :nth-child(2):before {
background-size: 2px;
background-image: url("http://r-g.esy.es/templates/web/images/noise.png");
height: 100%;
width: 100%;
position: absolute;
top: 0;
left: 0;
content: '';
}
</style>
</head>
<body></body>
</html>
Или же только псевдо-элементы