If you remove this method you get the following error:
gplus-photohunt-client-ios/PhotoHunt/HomeViewController.m:1054:15: No setter method 'setPhoto:' for assignment to property

HomeViewController
- (void)imagePickerController:(UIImagePickerController *) my_picker
didFinishPickingMediaWithInfo:(NSDictionary *)info
...
  photo.photo = useImage; // This line triggers the compile error