related_post_loop_item_element_post_thumb

remove_action('related_post_loop_item_element_post_thumb', 'related_post_loop_item_element_post_thumb', 10, 2);

add_action('related_post_loop_item_element_post_thumb', 'related_post_loop_item_element_post_thumb_20200126', 10, 2);

function related_post_loop_item_element_post_thumb_20200126($loop_post_id, $elementData)
{

    //$option_id_value = isset($elementData['option_id']) ? $elementData['option_id'] : '';
    //$post_meta_value = get_post_meta($loop_post_id, 'meta_key', true);
    $html_thumb = '';
    $thumb_linked = 'yes';
    $item_post_permalink = get_permalink($loop_post_id);
    $post = get_post($loop_post_id);
    $post_content = $post->post_content;
    $first_img = '';
    ob_start();
    ob_end_clean();
    $output = preg_match_all('/<img.+src=[\'"]([^\'"]+)[\'"].*>/i', $post_content, $matches);

    if (!empty($matches[1][0]))
        $first_img = isset($matches[1][0]) ? $matches[1][0] : '';

    if (empty($first_img)) {
        $html_thumb .= '';
    } else {

        if ($thumb_linked == 'yes') {
            $html_thumb .= '<a href="' . $item_post_permalink . '"><img src="' . $first_img . '" /></a>';
        } else {
            $html_thumb .= '<img src="' . $first_img . '" />';
        }
    }

    echo $html_thumb;
}