如何在MKAnnotation CalloutAccessoryView，swift 2.2中显示所选图像

// 在视图控制器中设置MKMapView的代理
class ViewController: UIViewController, MKMapViewDelegate {
    // ...
}

// 实现MKMapView的代理方法
extension ViewController: MKMapViewDelegate {
    func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
        if annotation is MKUserLocation {
            return nil
        }
        
        let reuseIdentifier = "CustomAnnotationView"
        var annotationView = mapView.dequeueReusableAnnotationView(withIdentifier: reuseIdentifier)
        
        if annotationView == nil {
            annotationView = CustomAnnotationView(annotation: annotation, reuseIdentifier: reuseIdentifier)
            annotationView?.canShowCallout = true
            
            let button = UIButton(type: .detailDisclosure)
            button.addTarget(self, action: #selector(buttonTapped), for: .touchUpInside)
            annotationView?.rightCalloutAccessoryView = button
        } else {
            annotationView?.annotation = annotation
        }
        
        return annotationView
    }
    
    @objc func buttonTapped() {
        let imagePickerController = UIImagePickerController()
        imagePickerController.delegate = self
        present(imagePickerController, animated: true, completion: nil)
    }
}

// 实现UIImagePickerController的代理方法
extension ViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [UIImagePickerController.InfoKey : Any]) {
        if let image = info[.originalImage] as? UIImage {
            // 在自定义MKAnnotationView中添加一个UIImageView，并将所选图像设置为其image属性
            // 例如：annotationView.imageView.image = image
        }
        
        picker.dismiss(animated: true, completion: nil)
    }
}