function jsDoImg3(imgname, thumbname, img1, img2) {
	var currimg = document.images[imgname].src;
	var z = currimg.lastIndexOf("/")
	if(z >= 0) {
		currimg = currimg.substr(z+1); }

	var newimg;
	if(currimg == thumbname)
		newimg = img1;
	else if(currimg == img1)
		newimg = img2;
	else if(currimg == img2)
		newimg = thumbname;
	else
		alert(currimg);

	document.images[imgname].src = newimg;
    return false;
}