title: Image stored as PFFile is not being saved - How do I ensure it gets saved eventually without freezing my app?
body: <p>As the title says, I have an image that I'm saving as a PFFile and trying to attach to an object. About 5% of the time, it doesn't save properly, which kind of sucks. I've reduced the size by a factor of 4, which helped a lot, but I can't reduce it much more without sacrificing too much quality.</p>
  
  <p>We have service providers who need to start going to their next job, so I can't just freeze them until the PFFile uploads. The issue is that they are in areas with poor cell signal. I don't know if it's getting cut off, or if it's just taking longer than the 3 seconds beforeSave allows before saving, but I need to find a solution to this.</p>
  
  <p>Right now, I'm creating the imageFile from the image, attaching it to a PFObject, then saving that object in the background. I know that I could add a block that sees if the save was successful, and if not, retry the save until it is, but as I said earlier, I don't want to freeze our providers until they get somewhere with enough service to get the save to go through.</p>
  
  <p>Is there a good way to create a background thread that attempts to save until the save is successful without being noticed by the main thread?</p>
  
  <p>One tricky bit may be that the view controller gets popped off as soon as the provider leaves their "job completed" view after where I try uploading this photo. However, I use an SWRevealViewController, so if I could somehow pass this PFFile to that other view controller before it's been successfully saved to a file, that would be ideal...</p>
  
  <p>Thanks for any tips and advice! </p>