function newImage(arg) {
	if (document.images) {
		rslt = new Image();
		rslt.src = arg;
		return rslt;
	}
}

function changeImages() {
	if (document.images && (preloadFlag == true)) {
		for (var i=0; i<changeImages.arguments.length; i+=2) {
			document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
		}
	}
}

var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		plan_10_plan_05_over = newImage("images/plan_10-plan_05_over.gif");
		plan_14_plan_23_over = newImage("images/plan_14-plan_23_over.gif");
		plan_17_plan_05_over = newImage("images/plan_17-plan_05_over.gif");
		plan_25_plan_15_over = newImage("images/plan_25-plan_15_over.gif");
		plan_28_plan_21_over = newImage("images/plan_28-plan_21_over.gif");
		preloadFlag = true;
	}
}