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

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

function changeImages() {
	changeImagesArray(changeImages.arguments);
}

function toggleImages() {
	for (var i=0; i<toggleImages.arguments.length; i+=2) {
		if (selected == toggleImages.arguments[i])      changeImagesArray(toggleImages.arguments[i+1]);
	}
}

var selected = '';
var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		home_over = newImage("images/home-over.gif");
		home_down = newImage("images/home-down.gif");
		week_over = newImage("images/week-over.gif");
		week_down = newImage("images/week-down.gif");
		choices_over = newImage("images/choices-over.gif");
		choices_down = newImage("images/choices-down.gif");
		official_over = newImage("images/official-over.gif");
		official_down = newImage("images/official-down.gif");
		form_over = newImage("images/form-over.gif");
		form_down = newImage("images/form-down.gif");
		preloadFlag = true;
	}
}