if (document) {
	img1on = new Image();      
	img1on.src = "images/nav_home_sbt.gif";
	img2on = new Image();      
	img2on.src = "images/nav_background_sbt.gif";
	img3on = new Image();      
	img3on.src = "images/nav_photography_sbt.gif";
	img4on = new Image();      
	img4on.src = "images/nav_exhibit_sbt.gif";
	img5on = new Image();      
	img5on.src = "images/nav_sponsors_sbt.gif";
	img6on = new Image();      
	img6on.src = "images/nav_hostit_sbt.gif";

	img1off = new Image(); 
	img1off.src = "images/nav_home_bt.gif";
	img2off = new Image(); 
	img2off.src = "images/nav_background_bt.gif";
	img3off = new Image(); 
	img3off.src = "images/nav_photography_bt.gif";
	img4off = new Image(); 
	img4off.src = "images/nav_exhibit_bt.gif";
	img5off = new Image(); 
	img5off.src = "images/nav_sponsors_bt.gif";
	img6off = new Image(); 
	img6off.src = "images/nav_hostit_bt.gif";
}

// Function to 'activate' images
function imgOn(imgName) {
	if (document) {
		document[imgName].src = eval(imgName + "on.src");
	}
}

// Function to 'deactivate' images
function imgOff(imgName) {
	if (document) {
		document[imgName].src = eval(imgName + "off.src");
	}
}