featured hay dùng để ảnh mặc định (ok)

$img_args = array(
        'alt' => get_the_title(),
        'class' => 'imgthank'
    );
<?php if ( get_the_post_thumbnail($article_post) ): ?>
  <?php print get_the_post_thumbnail($article_post, 'full', $img_args) ?>
<?php else: ?>
  <img src="<?php print site_url("wp-content/themes/genesis-sample/images/default.jpg")?>" class="news-featured-main_image">
<?php endif; ?>