Swift 3如何限制用户只拍摄照片而不是视频- iOS，Xcode

import UIKit

class ViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {

    @IBOutlet weak var imageView: UIImageView!
    
    // 当用户点击按钮时调用此函数
    @IBAction func takePhoto(_ sender: UIButton) {
        let imagePickerController = UIImagePickerController()
        imagePickerController.delegate = self
        imagePickerController.sourceType = .camera // 设置为相机
        imagePickerController.mediaTypes = ["public.image"] // 限制只能选择图片
        
        // 确保设备有相机功能
        if UIImagePickerController.isSourceTypeAvailable(.camera) {
            present(imagePickerController, animated: true, completion: nil)
        } else {
            // 处理没有相机的情况
            showAlert(message: "设备没有相机功能")
        }
    }
    
    // UIImagePickerControllerDelegate方法
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        if let selectedImage = info[.originalImage] as? UIImage {
            imageView.image = selectedImage
        }
        dismiss(animated: true, completion: nil)
    }
    
    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        dismiss(animated: true, completion: nil)
    }
    
    // 显示警告信息
    func showAlert(message: String) {
        let alert = UIAlertController(title: "提示", message: message, preferredStyle: .alert)
        alert.addAction(UIAlertAction(title: "确定", style: .default, handler: nil))
        present(alert, animated: true, completion: nil)
    }
}