public function getRules($relation, $input)
    {
        $child = $relation->getRelated();

        // If nested is not an Image, don't do anything special.  This will result
        // in the default validation behavior which gets the rules off of the child.
        if (!is_a($child, Image::class)) {
            return;
        }

        // Check for image rules on the parent
        $parent = $relation->getParent();
        $rules_key = 'images.' . ($input['name'] ?: 'default');
        if (!array_key_exists($rules_key, $parent::$rules)) {
            return;
        }

        // Return the parent rules concatenated on the default rules for an Image
        // (those are essentially hardcoded here but I don't expect them to change)
        return [
            'file' => 'image|' . $parent::$rules[$rules_key],
        ];
    }