realHeight = 1200;
realWidth = 772;

function showImage(divName, imgName)
{
	var availableWidth = document.documentElement.offsetWidth;
   	var availableHeight = document.documentElement.clientHeight;
	
	var width = availableWidth;
	var height = availableHeight;
	
	if (realHeight > availableHeight)
	{
	
		var factor = realHeight/availableHeight;
		
		height = availableHeight;		
		width = realWidth/factor;
		
	} else {
	
	if (realWidth > availableWidth)
	{
		var factor = realWidth/availableWidth;
		
		width = availableWidth;
		height = realHeight/factor;
	}
	}
	
	document.getElementById(imgName).width = width;
	document.getElementById(imgName).height = height;
	
	
	document.getElementById(divName).style.visibility='visible';
}


function full_size_image(divName, imgName)
{
	document.getElementById(imgName).width = realWidth;
	document.getElementById(imgName).height = realHeight;
}


function hideImage(divName, imgName)
{
	document.getElementById(divName).style.visibility='hidden';
}