WPSEO_Sitemap_Image_Parser::parse_galleries PHP Method

    private function parse_galleries($content, $post_id = 0)
    {
        $attachments = array();
        $galleries = $this->get_content_galleries($content);
        foreach ($galleries as $gallery) {
            $id = $post_id;
            if (!empty($gallery['id'])) {
                $id = intval($gallery['id']);
            }
            // Forked from core gallery_shortcode() to have exact same logic. R.
            if (!empty($gallery['ids'])) {
                $gallery['include'] = $gallery['ids'];
            }
            $gallery_attachments = array();
            if (!empty($gallery['include'])) {
                $_attachments = get_posts(array('include' => $gallery['include'], 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image'));
                foreach ($_attachments as $key => $val) {
                    $gallery_attachments[$val->ID] = $_attachments[$key];
                }
            } elseif (!empty($gallery['exclude']) && !empty($id)) {
                $gallery_attachments = get_children(array('post_parent' => $id, 'exclude' => $gallery['exclude'], 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image'));
            } elseif (!empty($id)) {
                $gallery_attachments = get_children(array('post_parent' => $id, 'post_status' => 'inherit', 'post_type' => 'attachment', 'post_mime_type' => 'image'));
            }
            $attachments = array_merge($attachments, $gallery_attachments);
        }
        return array_unique($attachments, SORT_REGULAR);
    }