取自 WordPress D8 主題;

路徑 theme/d8/modules ;

if ( ! function_exists( 'deel_thumbnail' ) ) :function deel_thumbnail() {      global $post;      if ( has_post_thumbnail() ) {           $domsxe = simplexml_load_string(get_the_post_thumbnail());        $thumbnailsrc = $domsxe->attributes()->src;          echo '<img src="'.$thumbnailsrc.'" alt="'.trim(strip_tags( $post->post_title )).'" />';    } else {        $content = $post->post_content;          preg_match_all('/<img.*?(?: |//t|//r|//n)?src=[/'"]?(.+?)[/'"]?(?:(?: |//t|//r|//n)+.*?)?>/sim', $content, $strResult, PREG_PATTERN_ORDER);          $n = count($strResult[1]);          if($n > 0){            echo '<img src="'.$strResult[1][0].'" alt="'.trim(strip_tags( $post->post_title )).'" />';          }else {            echo '<img src="'.get_bloginfo('template_url').'/img/thumbnail.png" alt="'.trim(strip_tags( $post->post_title )).'" />';          }      }}endif;