var $j = jQuery;
$j.fn.preload = function() {
	this.each(function(){
		$j('<img/>')[0].src = this;
	});
}

$j(['/themes/theme01/images/kart_ost.png','/themes/theme01/images/kart_vest.png','/themes/theme01/images/kart_nord.png','/themes/theme01/images/kart_midt.png']).preload();