function newPic(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}
	
function changePics() {
	if (document.images && (preloadFlag == true)) {
		for (var i=0; i<changePics.arguments.length; i+=2) {
		document[changePics.arguments[i]].src = changePics.arguments[i+1];
		}
	}
}
	
var preloadFlag = false;

function preloadPics() {
	if (document.images) {
		demo_slide1 = newPic("../images/demo_slide1.gif");
		demo_slide2 = newPic("../images/demo_slide2.gif");
		demo_slide3 = newPic("../images/demo_slide3.gif");
		preloadFlag = true;
	}
}