\n\nadd_action('wp_head', function() { global $post; $url = ''; if ($post && has_post_thumbnail($post->ID)) { $url = get_the_post_thumbnail_url($post->ID, 'full'); } if (!$url) { $imgs = get_posts(['post_type'=>'attachment','post_mime_type'=>'image','numberposts'=>1,'orderby'=>'date','order'=>'ASC']); if ($imgs) $url = wp_get_attachment_url($imgs[0]->ID); } if ($url) { echo '' . "\n"; echo '' . "\n"; } }, 5);