title: sync app captured images with icloud
body: <p>I am just learning core data and already I have the following task.
  I have an app which syncs core data with iCloud.
  Now I should provide feature according which user should be able to link images
  from camera roll with some entity. And as a result, that images also should be synced
  with iCloud.
  I know that I can create "image" entities, "connect" my existing entities with that and sync.
  But I know that images storing to core data is not preferable. 
  Therefore, I think the another option is to store images to some directory and sync that it.
  I'd like to know is the second option is possible to implement and integrate with already existing code.
  Also if it is possible please provide some examples.
  Thanks.    </p>