WordPress - Remove images older than three months

delete-old-non-featured-images.php

<?php
global $wpdb;

$attachment_ids = $wpdb->get_results(
  "SELECT
    ID 
  FROM
    {$wpdb->posts} 
  WHERE
    post_type = 'attachment' 
    AND post_date >= DATE_SUB(CURDATE(), INTERVAL 3 MONTH) 
    AND ID NOT IN 
    (
      SELECT
        meta_value 
      FROM
        {$wpdb->postmeta} 
      WHERE
        meta_key = '_post_thumbnail'
    )"
);

$attachment_ids = array_map(function($row) {
  return $row->ID;
}, $attachment_ids);

foreach ($attachment_id as $attachment_id) {
  $image_url = wp_get_attachment_image_src($attachment_id, 'full')[0];
  echo "Redirect 410 {$image_url}\n";
  wp_delete_attachment($attachment_id);
}