If you wanna do it in pure css you might break up the picture and then style it together like a pusle, And then give each brick a class which you style with different opacity
.test {
background-color: #6374AB;
width: 100%;
color: #ffffff;
}
.opaque1 { // for all other browsers
opacity: .5;
}
.opaque2 { // for IE5-7
filter: alpha(opacity=50);
}
.opaque3 { // for IE8
-ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=50)";
}
IE compatibility note
If you want opacity to work in all IE versions, the order should be:
.opaque {
-ms-filter:"progid:DXImageTransform.Microsoft.Alpha(Opacity=50)"; // first!
filter: alpha(opacity=50); // second!
}
Reference.