I've used this as a way to both apply colour tints as well as gradients to images to make dynamic overlaying text easier to style for legibility when you can't control image colour profiles. You don't have to worry about z-index.
HTML
<div class="background-image"></div>
SASS
.background-image {
background: url('../img/bg/diagonalnoise.png') repeat;
&:before {
content: '';
position: absolute;
top: 0;
left: 0;
right: 0;
bottom: 0;
background: rgba(248, 247, 216, 0.7);
}
}
CSS
.background-image {
background: url('../img/bg/diagonalnoise.png') repeat;
}
.background-image:before {
content: '';
position: absolute;
top: 0;
bottom: 0;
right: 0;
left: 0;
background: rgba(248, 247, 216, 0.7);
}
Hope it helps