var preImgOver = new Array();
var preImgOut = new Array();

$(function(){
	$('.iover').each(function(e){
		i = $(this).attr('id');
		sr = $(this).attr('src');
		s_o = sr.replace('.gif', '_over.gif');
		
		preImgOver[i] = new Image();
		preImgOver[i].src = s_o;
		preImgOut[i] = new Image();
		preImgOut[i].src = sr;
	});
	$('.iover').hover(function(){
		i = $(this).attr('id');
		$(this).attr('src', preImgOver[i].src);
	},
	function(){
		i = $(this).attr('id');
		$(this).attr('src', preImgOut[i].src);
	});
});