$(document).ready(function(){
	jQuery.preloadimages = function() {
		for(var i = 0; i<arguments.length; i++) {
			jQuery("<img>").attr("src", arguments[i]);
		}
	}
	
	$.preloadimages("images/nav-biography-over.gif", "images/nav-books-over.gif", "images/nav-events-over.gif", "images/nav-contact-over.gif", "images/nav-reading-groups-over.gif", "images/nav-news-over.gif");


    $(".hoverswap").hover(
        function () {
            $(this).attr("src", $(this).attr("src").replace(/.gif/, "-over.gif"));
        },
        function () {
            $(this).attr("src", $(this).attr("src").replace(/-over.gif/, ".gif"));
        }
    );


});