var winOpen = null

	function displayImage(picName, windowName, windowWidth, windowHeight){
	return window.open(picName,windowName,"toolbar=no,scrollbars=no,resizable=no,width=" + (parseInt(windowWidth)+0)  + ",height=" + (parseInt(windowHeight)+0)) 
	 }

	function winClose(){    // close all open pop-up windows   
	if(winOpen != null) winOpen.close() 
	}

	function Bild_vergroessern(){}  // does nothing but required by JavaScript in this case