$.preloadImages = function()
{
	for(var i = 0; i < arguments.length; i++)
	{
		$('<img>').attr('src', arguments[i]);
	}
}
$(document).ready(function()
{
	// set up rollover
	$.preloadImages('/wp-content/uploads/after_01.jpg', '/wp-content/uploads/after_02.jpg');
	$('#group1 img, #group2 img').hover
	(
		function()
		{
			$(this).attr('src', $(this).attr('src').replace('before_', 'after_')); // WITHOUT FADE
		},
		function()
		{
    		$(this).attr('src', $(this).attr('src').replace('after_', 'before_')); // WITHOUT FADE
		}
	);

});