if (document.images) {
	img1on = new Image();
	img1on.src = "http://www.tribee.com.br/rodape_royaltie/logot2.png";
	img1off = new Image();
	img1off.src = "http://www.tribee.com.br/rodape_royaltie/logot1.png"; 
}

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

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