function showPhotoPopup() {
	var overlay = document.getElementById('lertOverlay');
	var container = document.getElementById('lertContainer');
	var win = document.getElementById('lertWindow');

	//position and show the overlay and container
	overlay.style.height=getPageSize()[1]+'px';
	overlay.style.display='block';
	container.style.display = 'block';
	container.style.top = ( (getPageSize()[3] / 2) - (parseInt(win.offsetHeight,10) / 2)) + 'px';
}

function hidePhotoPopup() {
	document.getElementById('lertOverlay').style.display='none';
	document.getElementById('lertContainer').style.display='none';
	document.getElementById('lertWindow').src='';
}

// Returns array with page width, height and window width, height
function getPageSize(){
	var xScroll, yScroll;

	if (window.innerHeight && window.scrollMaxY) {
		xScroll = document.body.scrollWidth;
		yScroll = window.innerHeight + window.scrollMaxY;
	} else if (document.body.scrollHeight > document.body.offsetHeight){ // all but Explorer Mac
		xScroll = document.body.scrollWidth;
		yScroll = document.body.scrollHeight;
	} else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari
		xScroll = document.body.offsetWidth;
		yScroll = document.body.offsetHeight;
	}

	var windowWidth, windowHeight;
	if (self.innerHeight) {	// all except Explorer
		windowWidth = self.innerWidth;
		windowHeight = self.innerHeight;
	} else if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode
		windowWidth = document.documentElement.clientWidth;
		windowHeight = document.documentElement.clientHeight;
	} else if (document.body) { // other Explorers
		windowWidth = document.body.clientWidth;
		windowHeight = document.body.clientHeight;
	}

	// for small pages with total height less then height of the viewport
	if(yScroll < windowHeight) pageHeight = windowHeight;
	else pageHeight = yScroll;

	// for small pages with total width less then width of the viewport
	if(xScroll < windowWidth) pageWidth = windowWidth;
	else pageWidth = xScroll;

	arrayPageSize = new Array(pageWidth,pageHeight,windowWidth,windowHeight)
	return arrayPageSize;
}