title: UIActivityViewController share image only for FB, Twitter and Mail, but not messages
body: <p>So I am using the following code to get the text for all the UIActivityTypes. </p>
  
  <pre><code>        @objc func activityViewControllerPlaceholderItem(activityViewController: UIActivityViewController) -&gt; AnyObject {
          return ""
      }
  
      @objc func activityViewController(activityViewController: UIActivityViewController, itemForActivityType activityType: String) -&gt; AnyObject? {
          if activityType == UIActivityTypeMessage {
              return "String for message"
          } else if activityType == UIActivityTypeMail {
              return "String for mail"
          } else if activityType == UIActivityTypePostToTwitter {
              return "String for twitter"
          } else if activityType == UIActivityTypePostToFacebook {
              return "String for facebook"
          }
          return nil
      }
  
      func activityViewController(activityViewController: UIActivityViewController, subjectForActivityType activityType: String?) -&gt; String {
          if activityType == UIActivityTypeMessage {
              return "Subject for message"
          } else if activityType == UIActivityTypeMail {
              return "Subject for mail"
          } else if activityType == UIActivityTypePostToTwitter {
              return "Subject for twitter"
          } else if activityType == UIActivityTypePostToFacebook {
              return "Subject for facebook"
          }
          return ""
      }   
  }
  </code></pre>
  
  <p>And this is where the interesting part happens. I add an image from an URL to the objectsToShare array. This would work fine if I wanted the image to be shown for all, but my issue is that I don't want to show the image for the <code>UIActivityTypeMessage</code>. That one should just contain the text, and no image. How can I do this?</p>
  
  <pre><code>    // Load image to share
  let articleURL = URLBuilder.sharedInstance.addOnlyHttps((promo?.imageUrl)!)
  KingfisherManager.sharedManager.cache.retrieveImageForKey(articleURL, options: nil) { (image, _) -&gt; () in
      if image != nil {
          objectsToShare.append(image!)
          self.openShareViewController(objectsToShare, sender: sender )
      } else {
          KingfisherManager.sharedManager.downloader.downloadImageWithURL(NSURL(string: articleURL)!, progressBlock: nil, completionHandler: { (image, error, imageURL, originalData) in
              if image != nil {
                  KingfisherManager.sharedManager.cache.storeImage(image!, forKey: articleURL)
                  objectsToShare.append(image!)
                  self.openShareViewController(objectsToShare, sender: sender)
              }
          })
  
      }
  }
  </code></pre>