title: How to append data to a JSON value of type array in swift 4
body: <p>This is my code of the json object. I'm trying to get an image dictionary into the images value. I've tried a lot of things and maybe I'm missing something. </p>
  
  <pre><code> let jsonObject: [String: Any] = [
          "name_space": "users",
          "data_collection": "data://brownfosman5000/DatFace/",
          "action" : "add_images",
          "images": []
      ]
  </code></pre>
  
  <p>I have created a json dictionary to hold the images</p>
  
  <pre><code>let imageDictionary = try! JSONSerialization.jsonObject(with: imageJSON, options: []) as! [String : Any]
  </code></pre>
  
  <p>I have also created an array to hold the array of imageDictionaries</p>
  
  <pre><code>let images:NSMutableArray = NSMutableArray()
  self.images.add(imageDictionary)
  </code></pre>
  
  <p>How can I add the images array to the array in my json as a dictionary?
  Everything prints out nice I just need to add it to the json.</p>