WordPress - Первая картинка из записи вместо миниатюры

function first_post_image() {
  global $post, $posts;
  $first_img = '';
  ob_start();
  ob_end_clean();
  $output = preg_match_all('/<img.+src=[\'"]([^\'"]+)[\'"].*>/i', $post->post_content, $matches);
  $first_img = $matches [1] [0];
  if(empty($first_img)){
   $first_img = "/wp-content/themes/theme/images/noimages.jpg";
  }
  return $first_img;
}

<div id="post-<?php the_ID(); ?>" <?php post_class("col-md-4 col-sm-6 bgs-post home-post"); ?>>
    <div class="post-inner">
        <div class="img-thumbnail">
            <?php if(has_post_thumbnail()): ?>
            <?php the_post_thumbnail('storeone-thumb', array( 'class' => 'img-responsive' )); ?>
            <?php else: ?>
            <img src="<?php echo esc_url(get_template_directory_uri().'/images/featured-image-340x225.png'); ?>" class="img-responsive">
            <?php endif; ?>
            <div class="overlay">
                <a class="bgs-blog-more" href="<?php the_permalink(); ?>" title="<?php esc_attr_e('Read More', 'storeone'); ?>"><i class="fa fa-angle-right"></i></a>
            </div>
        </div>
        <div class="bgs-post-content">
            <time class="bgs-date entry-date published" datetime="<?php echo esc_attr( get_the_date( 'c' )); ?>">
                <div class="bds-date-block bds-day"><?php the_time( 'd',  get_the_ID()); ?></div>
                <div class="bds-date-block bds-month"><?php the_time( 'M, Y',  get_the_ID()); ?></div>
            </time>
            <?php the_title( '<h2 class="entry-title"><a href="' . esc_url( get_permalink() ) . '" rel="bookmark">', '</a></h2>' ); ?>
            <div class="entry-summary"><?php the_excerpt(); ?></div>
            <div class="clearfix"></div>
        </div>
    </div>
</div>

<img src="<?php echo esc_url(get_template_directory_uri().'/images/featured-image-340x225.png'); ?>" class="img-responsive">

<img src="<?php echo first_post_image() ?>" alt="<?php the_title(); ?>" class="img-responsive">