*{margin:0; padding:0;}

.portfolio{width:500px; margin:0 auto; position:relative;}
.portfolio_item{position:relative; margin:0 auto;}

.image_wrap{
	width:500px;
	height:350px;
	display:table-cell;
	text-align:center;
	vertical-align:middle;
	position:relative;
	cursor:pointer;
}
.image_wrap > img{
	vertical-align:middle;
	margin:0 auto;
	position:relative;
}
.zoom_overlay{
	width:400px;
	height:400px;
	margin:-200px 0px 0px -200px;
	background:transparent url(../img/overlay.png) repeat top left;
	position:absolute;
	top:50%;
	left:50%;
	display:none;
	opacity:0;
	-moz-border-radius:25px;
	-webkit-border-radius:25px;
	border-radius:25px;
	cursor:pointer;
	filter:progid:DXImageTransform.Microsoft.Alpha(opacity=0);
}

.zoom_overlay img{display:none;}