This is pretty close: http://jsfiddle.net/LfXN3/8/
But, it requires a second element (not image, just element). The pseudo-element approach wasn't working because the opacity of it couldn't be animated.
<div>
<div id="overlay"></div>
</div>?
CSS
div{
background:url(http://placekitten.com/600/600) center center;
width:400px;
height:400px;
-webkit-transition:all 2s;
-webkit-filter: grayscale(100%);
}
div:hover{
-webkit-filter: grayscale(0%);
}
div #overlay{
opacity:.5;
display:block;
background: -webkit-linear-gradient(45deg, #777 25%, transparent 25%, transparent), -webkit-linear-gradient(-45deg, #777 25%, transparent 25%, transparent), -webkit-linear-gradient(45deg, transparent 75%, #777 75%), -webkit-linear-gradient(-45deg, #000 75%, #777 75%);
background-size:2px 2px;
width:400px;
height:400px;
-webkit-transition:opcaity 2s;
}
div:hover #overlay{
opacity:0;
}
I've managed to get that tiny bit closer by incorporating Dudley Storey's technique into mine: http://jsfiddle.net/LfXN3/14/
The main difference being this:
div #overlay{
opacity:1;
display:block;
background: -webkit-radial-gradient(rgba(0,0,0,0) 45%, rgba(0,0,0,0.4) 46%),
-webkit-radial-gradient(rgba(0,0,0,0) 45%, rgba(0,0,0,0.4) 46%),
url(http://placekitten.com/600/600);
background-position: 0 0, 2px 2px, center center;
background-size:4px 4px, 4px 4px, 600px 600px;
width:400px;
height:400px;
-webkit-transition:opacity 2s;
}