SDWebImageTest.swift

import UIKit
import SDWebImage

class ViewController: UIViewController {
    let testURL = "https://i.groupme.com/638x640.jpeg.d4f31c747b534baca03d12db5a2b6193"
    var storeImg: UIImageView!

    override func viewDidLoad() {
        super.viewDidLoad()
        storeImg = UIImageView()
        storeImg.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(storeImg)
        storeImg.topAnchor.constraint(equalTo: view.safeAreaLayoutGuide.topAnchor).isActive = true
        storeImg.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
        storeImg.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
        storeImg.bottomAnchor.constraint(equalTo: view.safeAreaLayoutGuide.bottomAnchor).isActive = true
        if let url = URL(string: testURL), !(testURL.isEmpty) {
            storeImg.sd_setImage(with: url, placeholderImage: UIImage(named: "img-placeholder")) {
                (image, error, cache, url) in
                print("image \(String(describing: image))")
                print("error \(String(describing: error?.localizedDescription))")
                print("cache \(cache)")
                print("url \(String(describing: url))")
                if(error != nil) { }
            }
        } else {
            self.storeImg.image = UIImage(named: "img-placeholder")
        }
    }
}