Name when I capture photography on Swift

I'm trying to take a picture and save it with a name, but I do not know if I'm doing it right.

What I want to do is to send it to a server through a WebService, but I can not make the image save with the name I'm placing it.

I am developing it in Xcode 9 and Swift 4.

This is my code to open the camera:

func openCamera(){
        if UIImagePickerController.isSourceTypeAvailable(.camera){
            if((UIImagePickerController.availableCaptureModes(for: .rear)) != nil){
                imagePicker.allowsEditing = false;
                imagePicker.sourceType = .camera;
                imagePicker.cameraCaptureMode = .photo;
                present(imagePicker, animated: true, completion: nil);
            }
        }
    }
extension ClassViewController: UIImagePickerControllerDelegate, UINavigationControllerDelegate {
    func imagePickerController(_ picker: UIImagePickerController, didFinishPickingMediaWithInfo info: [String : Any]) {
        let imageName = "img_\(Date().timeIntervalSince1970).jpg";
        print("Tag: Nombre de la imagen es: ", imageName);
        if let imagenSeleccionada:UIImage = info[UIImagePickerControllerOriginalImage] as? UIImage{
            ImgFotografia.image = imagenSeleccionada;
            UIImageWriteToSavedPhotosAlbum(imagenSeleccionada, nil, nil, nil);
        }
        imagePicker.dismiss(animated: true, completion: nil);
    }
}