<div class="container">
<div class="element"></div>
</div>
body {
background-color: #F5F5F5;
color: #555;
font-size: 1.1em;
font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
}
hr {
margin: 50px 0;
}
.container {
margin: 40px auto;
max-width: 700px;
}
.element {
border: 1px solid #eee;
height: 300px;
background: url(http://tympanus.net/codrops-playground/assets/images/cssref/datatypes/calc/roses-1.jpg), url(http://tympanus.net/codrops-playground/assets/images/cssref/datatypes/calc/roses-2.jpg);
background-repeat: no-repeat;
background-color: white;
background-position: calc(50% + 20px) calc(50% + 20px), 50% 50%;
}