Simple Slideimg with jQuery (WP)

index.php

<div class="bgslide">
  <img src="<?php bloginfo('template_url');?>/images/slide1.png" class="active">
  <img src="<?php bloginfo('template_url');?>/images/slide2.png">
</div>

script.js

//slidebg
function slideSwitch() {
    var $active = $('.bgslide img.active');
    if ( $active.length == 0 ) $active = $('.bgslide img:last');
    var $next =  $active.next().length ? $active.next()
        : $('.bgslide img:first');
    $active.addClass('last-active').animate({opacity: 0.0}, 1000);
    $next.css({opacity: 0.0})
        .addClass('active')
        .animate({opacity: 1.0}, 1000, function() {
            $active.removeClass('active last-active');
        });
}

$(function() {
    setInterval( "slideSwitch()", 5000 );
});