HTML:
<div class="bg-img"></div>
CSS:
html, body {
width: 100%;
height: 100%;
}
.bg-img {
width: 100%;
height: 100%;
background: url('https://dl.dropboxusercontent.com/u/5049340/office%402x.png') center center no-repeat;
background-size: cover;
&:before {
content: '';
position: absolute;
top: 0;
right: 0;
bottom: 0;
left: 0;
background-image: linear-gradient(to bottom right,#002f4b,#dc4225);
opacity: .6;
}
}