function slideImages($slider){
      var $active = $slider.find('.active');
      var $next = ($active.next().length > 0) ? $active.next() : $slider.find('img:first');
      $next.css('z-index',2);//set the z-index so the image will slide across the top of  current one
      $active.css('z-index',1);//and set the current active image so it's below>
      $next.animate({left:0},"slow",function(){//slide in the next image

              $next.addClass('active');//and set the new image to active
        });
    }

    $(document).ready(function(){
    // run every 1s
    $('.portfolio_slider').on('mouseover', function(){
      var $this = $(this);
        setInterval(function(){
          slideImages($this);
        }, 1000);
        $(this).off('mouseover');

    })
})