path:
            path of the source image

def get_thumbsdir(self, path):
        """
        path:
            path of the source image
        """
        # Thumbsdir could be a callable
        # In that case, the path is built on the fly, based on the source path
        thumbsdir = self.thumbsdir
        if callable(self.thumbsdir):
            thumbsdir = self.thumbsdir(path)
        return thumbsdir