Swift 3; photo is not saving to photo gallery

Question

This code features a special camera that features a camera with a title nested in it. So when the photo is saved to the photo gallery the title is on the photo. The camera works great but the photo is not being saved. I just need to figure out how to save the photos to the photo gallery. I did change the plist to allow access to photo gallery and camera.

import Foundation
  import UIKit



class ViewController: UIViewController, OverlayViewControllerDelegate, UIImagePickerControllerDelegate, UINavigationControllerDelegate {

var picker = UIImagePickerController()

@IBAction func letsDoThis(_ sender: AnyObject) {
             if UIImagePickerController.availableCaptureModes(for: .rear) != nil {
        picker = UIImagePickerController()
        picker.allowsEditing = false
        picker.sourceType = .camera
        picker.cameraCaptureMode = .photo
        picker.showsCameraControls = false
        let overlayViewController = OverlayViewController(nibName:"OverlayView", bundle: nil)
        let overlayView: OverlayView = overlayViewController.view as! OverlayView
        overlayView.frame = self.picker.view.frame

        overlayView.delegate = self

        picker.modalPresentationStyle = .fullScreen
        present(picker, animated: true, completion: {


            self.picker.cameraOverlayView = overlayView
        })
    } else {
        let alert = UIAlertController(title: "No Camera", message: "That's weird. No camera.", preferredStyle: .alert)
        let okay = UIAlertAction(title: "Alright Then.", style: .default, handler: nil)
        alert.addAction(okay)
        present(alert, animated: true, completion: nil)
    }
}



override func viewDidLoad() {
    super.viewDidLoad()
           picker.delegate = self
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    picker.dismiss(animated: true, completion: nil)
}

//MARK: Image Picker Controller Delegates

func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
    let chosenImage = info[UIImagePickerControllerOriginalImage] as! UIImage
    UIImageWriteToSavedPhotosAlbum(chosenImage, self,nil, nil)

        dismiss(animated: true, completion: nil)
}

func imagePickerControllerDidCancel(_ picker: UIImagePickerController) {
    dismiss(animated: true, completion: nil)
    print("Canceled!!")
}

func didCancel(overlayView: OverlayView) {
    dismiss(animated: true, completion: nil)
    print("dismissed!!")
}
func didShoot(overlayView: OverlayView) {
    picker.takePicture()
    overlayView.cameraLabel.text = "Shot Photo"
    print("Shot Photo")
}
}

Answer 1

This might not the solution, but maybe it will take you further why the image is not saved (Hint from rmaddy in the comments of question). To see if there is an error while saving, use the completionTarget and completionSelector parameters like that (See also the docs):

Add the completionSelector method:

func image(_ image: UIImage, didFinishSavingWithError error: Error?, contextInfo: UnsafeMutableRawPointer) {
  guard error == nil else {
    print("Error saving image: \(error)")
    return
  }    
  print("Image saved successfully")
}

Change UIImageWriteToSavedPhotosAlbum to this

UIImageWriteToSavedPhotosAlbum(chosenImage, self, #selector(self.image(_:didFinishSavingWithError:contextInfo:)), nil)