function preloadImages() {
	imgs = ["./images/button_pres.png","./images/button_advan.png","./images/button_works.png",
			"./images/button_company.png","./images/button_mobile.png","./images/button_web.png",
			"./images/button_pub.png","./images/button_consul.png","./images/menu_outline.png",
			"./images/menu_mobile.png","./images/menu_web.png","./images/menu_pub.png","./images/menu_consul.png"];
	prImage = new Array();
	for(i = 0; i < imgs.length; i++){
		prImage[i] = new Image();
		prImage[i].src = imgs[i];
	}
}