      def _crop_source_faces(self):
          """ Extract the source faces from the source frames, along with their filenames and the
          transformation matrix used to extract the faces. """
          logger.debug("Updating source faces")
          self._faces = dict()
          for image in self.source:
              detected_face = image["detected_faces"][0]
              src_img = image["image"]
              detected_face.load_aligned(src_img, size=self._size, centering=self._centering)
              matrix = detected_face.aligned.matrix
 
</s> remove                                    list()).append(os.path.splitext(image["filename"])[0])
            self._faces.setdefault("matrix", list()).append(matrix)
            self._faces.setdefault("src", list()).append(transform_image(src_img,
                                                                         matrix,
                                                                         self._size,
                                                                         self._padding))
 </s> add                                    []).append(os.path.splitext(image["filename"])[0])
            self._faces.setdefault("matrix", []).append(matrix)
            self._faces.setdefault("src", []).append(transform_image(src_img,
                                                                     matrix,
                                                                     self._size,
                                                                     self._padding)) </s> remove         self._faces["dst"] = list()
 </s> add         self._faces["dst"] = [] </s> remove         swapped = list()
 </s> add         swapped = [] </s> remove                 self.tk_vars.setdefault(section, dict())[key] = cp_option.tk_var
                config_dicts.setdefault(section, dict())[key] = cp_option
 </s> add                 self.tk_vars.setdefault(section, {})[key] = cp_option.tk_var
                config_dicts.setdefault(section, {})[key] = cp_option </s> remove             self._predicted_images = list()
 </s> add             self._predicted_images = []
        self._faces = {}
      def _crop_source_faces(self):
          """ Extract the source faces from the source frames, along with their filenames and the
          transformation matrix used to extract the faces. """
          logger.debug("Updating source faces")
        self._faces = {}
          for image in self.source:
              detected_face = image["detected_faces"][0]
              src_img = image["image"]
              detected_face.load_aligned(src_img, size=self._size, centering=self._centering)
              matrix = detected_face.aligned.matrix
keep keep keep keep replace keep keep keep keep keep
 bugfix: Preview Tool, ensure all config items are written 
tools/preview/preview.py