I saw some similar questions regarding this. But my approach is different and none of those works to me. That's why I'm posting this. I want to change the opacity of background image without changing the opacity of child elements, where background-image is loaded inside the body tag.
html :
<body>
<div id = "background-div">
<div class = "header">
<div class = "ham-icon">
<img src = "images/ham-icon.png">
</div>
<div class = "logo">
<span class = "google-logo">Google</span><span class = "hangouts-logo"> Hangouts</span>
</div>
<div class = "profile-data">
</div>
</div>
<div class = "body">
</div>
</div>
</body>
css:
body
{
position: relative;
background: url(../images/back1.jpg) no-repeat center center fixed;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
}