function showImageOverlay(imageUrl){
	var isIE = false;
	if(navigator.appName == "Microsoft Internet Explorer"){
		isIE = true;
	}
	
	var imagePtr = new Image();
	imagePtr.src = imageUrl;

	var width = imagePtr.width;
	var height = imagePtr.height;
	var screenWidth = document.body.clientWidth;
	var screenHeight = document.body.clientHeight;
	var left = (screenWidth/2) - (width/2);
	var top = (screenHeight/2) - (height/2);

	var overlay = document.getElementById("imageOverlay");

	if(isIE){
	//	overlay.style.top = document.body.scrollTop;
	}else{
	//	overlay.style.top = window.pageYOffset;
	}
	
	var closeleft = (left+width)-25;
	var closetop = top;

	overlay.innerHTML = '<div style="position: absolute; left: 0; top: 0; width: 100%; height: 100%; background-color: #222222; opacity: 0.75; filter: alpha(opacity=70); z-index: 2000;" onclick="hideImageOverlay();"></div>';
	overlay.innerHTML += '<div style="position: absolute; left: '+left+'; top: '+top+'; width: '+width+'; height: '+height+'; z-index: 2001; background-image: url('+imageUrl+');" onclick="hideImageOverlay();"></div>';
	
	overlay.style.visibility = "visible";

	return(false);
}

function hideImageOverlay(){
	document.getElementById("imageOverlay").style.visibility = "hidden";
}