def populate_from_settings(self):
        """
        Populate the aliases from the ``THUMBNAIL_ALIASES`` setting.
        """
        settings_aliases = settings.THUMBNAIL_ALIASES
        if settings_aliases:
            for target, aliases in settings_aliases.items():
                target_aliases = self._aliases.setdefault(target, {})
                target_aliases.update(aliases)
Populate the aliases from the ``THUMBNAIL_ALIASES`` setting.