Best way to save photo from URL, swift

Question

How to save photo? In swift Which way is better?

    @IBAction func savePhoto(_ sender: Any) {
        let imageData = UIImagePNGRepresentation(myImg.image!)
        let compresedImage = UIImage(data: imageData!)
        UIImageWriteToSavedPhotosAlbum(compresedImage!, nil, nil, nil)

        let alert = UIAlertController(title: "Saved", message: "Your image has been saved", preferredStyle: .alert)
        let okAction = UIAlertAction(title: "Ok", style: .default)
        alert.addAction(okAction)
        self.present(alert, animated: true)
    }   
}

Answer 1

This should work for you. Used this answer from Leo Dabus for the getDataFromUrl method to get the data from the URL:

Don't forget to add the key Privacy - Photo Library Additions Usage Description to your Info.plist with a description to explain the user why you need access to the photo library.

import UIKit

class ViewController: UIViewController, UIImagePickerControllerDelegate, UINavigationControllerDelegate {

    @IBOutlet var imageView: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }


    func getDataFromUrl(url: URL, completion: @escaping (Data?, URLResponse?, Error?) -> ()) {
        URLSession.shared.dataTask(with: url) { data, response, error in
            completion(data, response, error)
        }.resume()
    }


    @IBAction func savePhoto(_ sender: UIButton) {

        let yourImageURLString = "https://scontent-frx5-1.cdninstagram.com/t51.2885-15/e35/22794197_139950336649166_440006381429325824_n.jpg"

        guard let yourImageURL = URL(string: yourImageURLString) else { return }

        getDataFromUrl(url: yourImageURL) { (data, response, error) in

            guard let data = data, let imageFromData = UIImage(data: data) else { return }

            DispatchQueue.main.async() {
                UIImageWriteToSavedPhotosAlbum(imageFromData, nil, nil, nil)
                self.imageView.image = imageFromData

                let alert = UIAlertController(title: "Saved", message: "Your image has been saved", preferredStyle: .alert)
                let okAction = UIAlertAction(title: "Ok", style: .default)
                alert.addAction(okAction)
                self.present(alert, animated: true)
            }
        }

    }
}