Nette\Forms\Validator::validateMimeType PHP Метод

    public static function validateMimeType(Controls\UploadControl $control, $mimeType)
    {
        $mimeTypes = is_array($mimeType) ? $mimeType : explode(',', $mimeType);
        foreach (static::toArray($control->getValue()) as $file) {
            $type = strtolower($file->getContentType());
            if (!in_array($type, $mimeTypes, TRUE) && !in_array(preg_replace('#/.*#', '/*', $type), $mimeTypes, TRUE)) {
                return FALSE;
            }
        }
        return TRUE;
    }