Get the 100x100 thumbnail of a file. Return the raw PNG data.
        
        Parameters:
            * id: The Puush ID of the file to get the thumbnail of.

def thumbnail(self, id):
        """Get the 100x100 thumbnail of a file. Return the raw PNG data.
        
        Parameters:
            * id: The Puush ID of the file to get the thumbnail of.
        """
        res = self._raw_api_request('thumb', data={'i': id})
        if not res:
            raise PuushError("Getting thumbnail failed.")
        return res