如何使用UIImagePicker获取镜像名称？我得到了图像名称，但它只能在模拟器中工作，而不能在实际设备中工作

let imagePicker = UIImagePickerController()
imagePicker.delegate = self

imagePicker.sourceType = .photoLibrary
imagePicker.mediaTypes = [kUTTypeImage as String]

present(imagePicker, animated: true, completion: nil)

extension ViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        if let image = info[.originalImage] as? UIImage {
            // 处理选择的图像
            let imageName = generateImageName() // 生成图像名称的方法
            // 在此处使用图像名称进行后续操作
        }
        picker.dismiss(animated: true, completion: nil)
    }
    
    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        picker.dismiss(animated: true, completion: nil)
    }
}

func generateImageName() -> String {
    let timestamp = Int(Date().timeIntervalSince1970)
    return "image_\(timestamp).jpg"
}