// preloadimages 

	opticalhomeon =  new Image();
	opticalhomeon.src = "images/opticalhomeon.gif";
	opticalhomeoff = new Image();
	opticalhomeoff.src = "images/opticalhomeoff.gif";

	opticalabouton = new Image();
	opticalabouton.src = "images/opticalabouton.gif";						
	opticalaboutoff = new Image();
	opticalaboutoff.src = "images/opticalaboutoff.gif";

	opticalcontacton = new Image();
	opticalcontacton.src = "images/opticalcontacton.gif";	
	opticalcontactoff = new Image();
	opticalcontactoff.src = "images/opticalcontactoff.gif";	

	opticalon = new Image();
	opticalon.src = "images/opticalon.gif";	
	opticaloff = new Image();
	opticaloff.src = "images/opticaloff.gif";	

	trainingon = new Image();
	trainingon.src = "images/trainingon.gif";	
	trainingoff = new Image();
	trainingoff.src = "images/trainingoff.gif";

	developmenton = new Image();
	developmenton.src = "images/developmenton.gif";	
	developmentoff = new Image();
	developmentoff.src = "images/developmentoff.gif";
	
	// function to do rollovers on images
	function swapImage(num){
		if (num=="1") document.images ['opticalhome'].src = opticalhomeon.src;
		else if (num=="2") document.images ['opticalhome'].src = opticalhomeoff.src;				
		else if (num=="3") document.images ['opticalabout'].src = opticalabouton.src;	
		else if (num=="4") document.images ['opticalabout'].src = opticalaboutoff.src;	
		else if (num=="5") document.images ['opticalcontact'].src = opticalcontacton.src;
		else if (num=="6") document.images ['opticalcontact'].src = opticalcontactoff.src;				
		else if (num=="7") document.images ['optical'].src = opticalon.src;	
		else if (num=="8") document.images ['optical'].src = opticaloff.src;		
		else if (num=="9") document.images ['training'].src = trainingon.src;
		else if (num=="10") document.images ['training'].src = trainingoff.src;
		else if (num=="11") document.images ['development'].src = developmenton.src;	
		else if (num=="12") document.images ['development'].src = developmentoff.src;
	}