URLSession download images example | Swift 3

URLSession.swift

if let image = imageURL {
            let url = URL(string: image)
            URLSession.shared.dataTask(with: url!, completionHandler: { (data, response, error) in
                
                if error != nil {
                    print(error!)
                    return
                }

                DispatchQueue.main.async {
                    imageView.image = UIImage(data: data!)
                }
            }).resume()
}

it's nice and create extension like https://iosdevcenters.blogspot.com/2018/06/how-to-downloading-image-from-server.html

I am new in this.Can you please tell me how can you downloads 100 images asynchronously at a time using this?

how can we use this in collection view where is doesn't load all images some times repeat same image??