showPreviewImage-in-alert.swift

func showPreviewImage(image: UIImage)
    {
        let alert = UIAlertController(title: "Preview", message: "", preferredStyle: .actionSheet)
        alert.addPreviewImage(image: image)
alert.addAction(UIAlertAction(title: "Add To Photos", style: .default){
            action in
            UIImageWriteToSavedPhotosAlbum(image, self, nil, nil)
        })
        alert.addAction(UIAlertAction(title: "Cancel", style: .destructive, handler: nil))
        
        present(alert,
                    animated: true,
                    completion: nil)
    }