function preloader() {
	if (document.images) {

		var img1 = new Image();
		var img2 = new Image();
		
		img1.src = "img/vec_buttong.png";
		img1.src = "img/vec_buttong_hover.png";
			}
}

$(document).ready(function(){  
$("img.a").hover(  
function() {  
$(this).animate({"opacity": "0"}, "slow");  
},  
function() {  
$(this).animate({"opacity": "1"}, "slow");  
});  
   
 });