Transparent background images
HTML
<div class="ima">
<div class="txt">
This doesn't have opacity. Neither does its parent.
</div>
<div class="ima__transparency"></div>
</div>
CSS
.ima {
position: relative;
}
.ima__transparency {
background: url(http://www.lorempixel.com/640/480/abstract);
content: '';
position: absolute;
top: 0;
left: 0;
bottom: 0;
right: 0;
opacity: .5;
}
.txt {
position: relative;
z-index: 1;
}