title: Alamofire: Do af_setImageWithURL and ImageDownloader share the same AutoPurgingImageCache?
body: <p>I use AlamofireImage in my project a lot like this to set an image to an UIImageView:</p>
  
  <pre><code>let imageView = UIImageView(frame: frame)
  let URL = NSURL(string: "https://httpbin.org/image/png")!
  
  imageView.af_setImageWithURL(URL)
  </code></pre>
  
  <p>At some point in my app I need to get fetch an image directly, because I want to do something else than setting it to an UIImageView. AlamofireImage provides <code>ImageDownloader</code> for this usecase:</p>
  
  <pre><code>let downloader = ImageDownloader()
  let URLRequest = NSURLRequest(URL: NSURL(string: "https://httpbin.org/image/jpeg")!)
  
  downloader.downloadImage(URLRequest: URLRequest) { response in
      print(response.request)
      print(response.response)
      debugPrint(response.result)
  
      if let image = response.result.value {
          print(image)
      }
  }
  </code></pre>
  
  <p>Do these two cases <strong>share the same</strong> <code>AutoPurgingImageCache</code>?</p>