CameraRoll provides access to the local camera roll / gallery.
Saves the image to the camera roll / gallery.
The CameraRoll API is not yet implemented for Android.
@param {string} tag On Android, this is a local URI, such
as "file:///sdcard/img.png".
On iOS, the tag can be one of the following:
@param successCallback Invoked with the value of tag on success.
@param errorCallback Invoked with error message on error.
 Invokes callback with photo identifier objects from the local camera
 roll of the device matching shape defined by getPhotosReturnChecker.
 @param {object} params See getPhotosParamChecker.
 @param {function} callback Invoked with arg of shape defined by
 getPhotosReturnChecker on success.
 @param {function} errorCallback Invoked with error message on error.