private static function _createWbmp($imageFile)
{
$gd = @imagecreatefromwbmp($imageFile);
if (!$gd) {
throw new \Exception(sprintf('Could not open "%s". Not a valid %s file.', $imageFile, ImageType::WBMP));
}
return new self($gd, $imageFile, imagesx($gd), imagesy($gd), ImageType::WBMP);
}