var preloadFlag = false;
function preloadImages() {
	if (document.images) {
		pre_button7b = newImage('images/button7b.png');
		pre_button2b = newImage('images/button2b.png');
		pre_button3b = newImage('images/button3b.png');
		pre_button4b = newImage('images/button4b.png');
		pre_button5b = newImage('images/button5b.png');
		pre_button6b = newImage('images/button6b.png');
		pre_button8b = newImage('images/button8b.png');
		pre_yearbooks_down = newImage('images/yearbooks_down.png');
		preloadFlag = true;
	}
}