Fixed #12955 -- Use the size attribute of the file instead of len() to support...

    def _get_size(self):

        self._require_file()

        if not self._committed:

            return len(self.file)

            return self.file.size

        return self.storage.size(self.name)

    size = property(_get_size)

        setattr(self.instance, self.field.name, self.name)

        # Update the filesize cache

        self._size = len(content)

        self._size = content.size

        self._committed = True

        # Save the object because it has changed, unless save is False