if (document.images) {         
	spanneron = new Image();
	spanneron.src = "img/spanner2.gif";
	spanneroff = new Image();
	spanneroff.src = "img/spanner.gif";

	hyyumon = new Image();
	hyyumon.src = "img/hyyum2.gif";
	hyyumoff = new Image();
	hyyumoff.src = "img/hyyum.jpg";

	kernelon = new Image();
	kernelon.src = "img/kernel2.gif";
	kerneloff = new Image();
	kerneloff.src = "img/kernel.jpg";
}