Fix missing thumbnail for Auto Post Thumbnail plugin

fix-thumbnail.php

<?php

/**
 * Usage: upload to WP folder
 * Run it!
 */

echo 'Working... ';

require_once( 'wp-load.php' );

global $wpdb;

$atts = $wpdb->get_col("
	SELECT DISTINCT ID
	FROM {$wpdb->posts}
	WHERE post_type = 'attachment'
");
foreach ( $atts as $att )
{
	$sql = '';

	$check = $wpdb->get_col( "
		SELECT meta_id
		FROM {$wpdb->postmeta}
		WHERE post_id = '{$att}' AND meta_key = '_wp_attached_file'
	");

	// We've already done this one...
	if ( !empty( $check ) )
		continue;

	$thumb = $wpdb->get_row("
		SELECT meta_key, meta_value
		FROM {$wpdb->postmeta}
		WHERE post_id = '{$att}' AND meta_key = '_wp_attachment_metadata'
	");

	if ( empty( $thumb ) || !isset( $thumb->meta_value ) )
		continue;

	$data = unserialize( $thumb->meta_value );

	if ( !isset( $data['sizes']['thumbnail']['file'] ) )
		continue;
	
	$path = dirname( $data['file'] ) . '/' . $data['sizes']['thumbnail']['file'];
	
	$wpdb->query("
		INSERT INTO {$wpdb->postmeta}
		SET post_id='{$att}', meta_key='_wp_attached_file', meta_value='{$path}'
	");
}

echo 'Done!';