<!-- Begin
img15_on = new Image;
img15_on.src="http://www.junglephotos.com/galapagos/ggifs/gtop1.gif";
img15_off = new Image;
img15_off.src="http://www.junglephotos.com/galapagos/ggifs/gtop2.gif";
img16_on = new Image;
img16_on.src="http://www.junglephotos.com/galapagos/ggifs/gtop1.gif";
img16_off = new Image;
img16_off.src="http://www.junglephotos.com/galapagos/ggifs/gtop2.gif";
img17_on = new Image;
img17_on.src="http://www.junglephotos.com/galapagos/ggifs/gtop1.gif";
img17_off = new Image;
img17_off.src="http://www.junglephotos.com/galapagos/ggifs/gtop2.gif";

function over_image(parm_name)
{
document[parm_name].src = eval(parm_name + "_on.src");
}
function off_image(parm_name)
{
document[parm_name].src = eval(parm_name + "_off.src");
} 
End -->