if(document.images) {
  
	var beebeoff = new Image();  
	var beebeon = new Image();
	var ellsworthon = new Image();
	var ellsworthoff = new Image();
	var glennon = new Image();
	var glennoff = new Image();
	var pearyon = new Image();
	var pearyoff = new Image();
	var roosevelton = new Image();
	var rooseveltoff = new Image();
	
	beebeoff.src = "images/beebe_off.gif";  
	beebeon.src = "images/beebe_on.gif";
	ellsworthoff.src = "images/ellsworth_off.gif";  
	ellsworthon.src = "images/ellsworth_on.gif";
	glennoff.src = "images/glenn_off.gif";  
	glennon.src = "images/glenn_on.gif";
	pearyoff.src = "images/peary_off.gif";  
	pearyon.src = "images/peary_on.gif";
	rooseveltoff.src = "images/roosevelt_off.gif";  
	roosevelton.src = "images/roosevelt_on.gif";
}


function off(imgName) {
	if(document.images) {
	document[imgName].src = eval(imgName + 'off.src');
	}
}

function on(imgName) {
	if(document.images) {
	document[imgName].src = eval(imgName + 'on.src');
	}
}