extract_attachment_ids

function extract_attachment_ids($post) {
$reslt=[];
$attachments=wp_get_attached_media('',$post->ID);
if (count($attachments)) {
array_push($reslt, array_map(function ($o) {return $o->ID;},$attachments);
}
return $reslt;
}

/* array for id of images to be deleted */
$rosies_images_to_be_deleted = [];

$args = array(
    'posts_per_page' => '999',
    'post_type' => 'product'
);
$my_query = new WP_Query($args);

if ($my_query->have_posts()) {
 while ($my_query->have_posts()) { $my_query->the_post();
array_push($rosies_images_to_be_deleted, ... extract_attachment_ids($post));
}
?>