在Swift 3中，如何在Pickerview Controller中更改所选图像的分辨率

let imagePicker = UIImagePickerController()
imagePicker.sourceType = .photoLibrary

imagePicker.delegate = self

extension ViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        if let image = info[.originalImage] as? UIImage {
            // 在这里对所选图像进行分辨率更改
            let resizedImage = resizeImage(image: image, targetSize: CGSize(width: 800, height: 600))
            // 使用更改后的图像进行后续操作
        }
        picker.dismiss(animated: true, completion: nil)
    }
    
    func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
        picker.dismiss(animated: true, completion: nil)
    }
    
    // 辅助方法：调整图像分辨率
    func resizeImage(image: UIImage, targetSize: CGSize) -> UIImage {
        let size = image.size
        
        let widthRatio  = targetSize.width  / size.width
        let heightRatio = targetSize.height / size.height
        
        let newSize: CGSize
        if widthRatio > heightRatio {
            newSize = CGSize(width: size.width * heightRatio, height: size.height * heightRatio)
        } else {
            newSize = CGSize(width: size.width * widthRatio, height: size.height * widthRatio)
        }
        
        let rect = CGRect(x: 0, y: 0, width: newSize.width, height: newSize.height)
        UIGraphicsBeginImageContextWithOptions(newSize, false, 1.0)
        image.draw(in: rect)
        let newImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        
        return newImage!
    }
}