[madmeur]

$(this.scroll_back).add(this.scroll_forward).click(
        function() {
          // We don't want to jump the whole width, since an image
          // might be cut at the edge
          var width = context.nav_display_width - 50;
          if(context.settings.scroll_jump > 0) {
            var width = context.settings.scroll_jump;
          };
          if($(this).is('.ad-forward')) {
            var left = context.thumbs_wrapper.scrollLeft() + width;
          } else {
            var left = context.thumbs_wrapper.scrollLeft() - width;
          };
          if(context.settings.slideshow.stop_on_scroll) {
            context.stopSlideshow();
          };
          if(context.settings.animated_scroll) {
            context.thumbs_wrapper.animate({scrollLeft: left +'px'});
          } else {
            context.thumbs_wrapper.scrollLeft(left);
          };
          return false;
        }
      )

Функция animated_scroll.