<?php

$host = 'localhost';
$dbname = 'spirit';
$user = 'spirit';
$password = 'spirit';

$dsn = "mysql:host={$host};dbname={$dbname};charset=UTF8";
$opt = [PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC];
$pdo = new PDO($dsn, $user, $password, $opt);

$incompletesStmt = $pdo->query('SELECT * FROM (SELECT count(*) AS cnt_total, count(image) AS cnt_not_null, pagetitle, min(image) AS image FROM modx_ms2_products AS p LEFT JOIN modx_site_content AS c ON p.id = c.id GROUP BY pagetitle) AS t WHERE cnt_total > cnt_not_null');
$idsStmt = $pdo->prepare('SELECT id, pagetitle FROM modx_site_content WHERE pagetitle = :title');

while ($row = $incompletesStmt->fetch()) {

    if ($row['cnt_not_null'] == '0') {
        print('NO IMAGE ' . $row['pagetitle'] . "\n");
    } else {
        $idsStmt->execute(['title' => $row['pagetitle']]);
        $ids = $idsStmt->fetchAll();
        $ids = array_column($ids, 'id');

        $placeholders = str_repeat ('?, ',  count($ids) - 1) . '?';
        $updateStmt = $pdo->prepare("UPDATE modx_ms2_products SET image=? WHERE id IN ($placeholders) AND image IS NULL");
        array_unshift($ids, $row['image']);
        $updateStmt->execute($ids);
    }
}