function win8_gallery_shortcode( $attr ) {
    global $post;

    static $instance = 0;
    $instance++;

    $output = '';

    // We're trusting author input, so let's at least make sure it looks like a valid orderby statement
    if ( isset( $attr['orderby'] ) ) {
      $attr['orderby'] = sanitize_sql_orderby( $attr['orderby'] );
      if ( !$attr['orderby'] )
        unset( $attr['orderby'] );
    }

    extract( shortcode_atts( array(
      'order'     => 'ASC',
      'orderby'   => 'menu_order ID',
      'id'        => $post->ID,
      'include'   => '',
      'exclude'   => '',
      'slideshow' => false
    ), $attr, 'gallery' ) );

    // Custom image size and always use it
    add_image_size( 'win8app-column', 480 );
    $size = 'win8app-column';

    $id = (int) $id;
    if ( 'RAND' === $order )
      $orderby = 'none';

    if ( !empty( $include ) ) {
      $include      = preg_replace( '/[^0-9,]+/', '', $include );
      $_attachments = get_posts( array( 'include' => $include, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby ) );
      $attachments  = array();
      foreach ( $_attachments as $key => $val ) {
        $attachments[$val->ID] = $_attachments[$key];
      }
    } elseif ( !empty( $exclude ) ) {
      $exclude     = preg_replace( '/[^0-9,]+/', '', $exclude );
      $attachments = get_children( array( 'post_parent' => $id, 'exclude' => $exclude, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby ) );
    } else {
      $attachments = get_children( array( 'post_parent' => $id, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image', 'order' => $order, 'orderby' => $orderby ) );
    }

    if ( ! empty( $attachments ) ) {
      foreach ( $attachments as $id => $attachment ) {
        $link = isset( $attr['link'] ) && 'file' === $attr['link'] ? wp_get_attachment_link( $id, $size, false, false ) : wp_get_attachment_link( $id, $size, true, false );

        if ( $captiontag && trim($attachment->post_excerpt) ) {
          $output .= "<div class='wp-caption aligncenter'>$link
						<p class='wp-caption-text'>" . wptexturize($attachment->post_excerpt) . "</p>
						</div>";
        } else {
          $output .= $link . ' ';
        }
      }
    }
  }