title: Recommended folder to save on demand images for an IOS and Mac App?
body: <p>My app uses custom skins (themes) but I don't want to package them all with the app due to the increasing size. 
  When the user selects the skin, it will download image resources from my server. </p>
  
  <p>The question is, where would be the recommended directory to save the files ? To the document directory ? I'm guessing I will not get the benefits of the UIImage(named:) cache system, nor the automatic scale selection ?</p>