function showRandomImage(extension) {
	var nImage=3;
	var sExtension=new String('.jpg');
	var nRandom=Math.random();
	var rand1=Math.round(nImage * nRandom)
	if (rand1==3) {
		rand1--;
		}
	
	var images=new Array();
	images[0]=extension+1+sExtension;
	images[1]=extension+2+sExtension;
	images[2]=extension+3+sExtension;
	var finalImage=images[rand1];
	//alert(finalImage+', '+rand1);
	var output="<img src='../images/masthead_images/";
	output+=finalImage;
	output+="'>";
	document.write(output);
	
}