[Auto Post Thumbnail] Fix uploaded thumbnails

<?php
// Based on Neil Paterson's code:
// http://www.clickthrough-marketing.com/how-to-fix-auto-post-thumbnail-on-wordpress-3.4-seo-friendly-800610805/

ob_implicit_flush( 1 );
require_once( 'wp-load.php' );
echo 'Working... ';

$sql = "SELECT meta_value FROM $wpdb->postmeta WHERE meta_key = '_thumbnail_id' ORDER BY post_id DESC";

$posts = $wpdb->get_results( $sql );
foreach ( (array) $posts as $post ) {
    $sql = $wpdb->prepare( "SELECT meta_id FROM $wpdb->postmeta WHERE post_id = %d AND meta_key = '_wp_attached_file'", $post->meta_value );
    $check = $wpdb->get_results( $sql );
    if ( count( $check ) )
        continue; // We've already done this one...

    $sql = $wpdb->prepare( "SELECT meta_key, meta_value FROM $wpdb->postmeta WHERE post_id = %d AND meta_key = '_wp_attachment_metadata'", $post->meta_value );
    $thumb = $wpdb->get_results( $sql );
    if ( ! empty( $thumb ) )
        $data = unserialize( $thumb[0]->meta_value );
    if ( ! isset( $data['file'] ) )
        continue;

    $sql = $wpdb->prepare( "INSERT INTO $wpdb->postmeta SET post_id = %d, meta_key = '_wp_attached_file', meta_value = %s", $post->meta_value, $data['file'] );
    $wpdb->query( $sql );
}

echo 'Done!';
?>