Upload a photo to a dataset's gallery.

def upload_gallery_photo(self, gallery_id, source_amigo_id, file_obj,
                             chunk_size=CHUNK_SIZE, force_chunked=False,
                             metadata=None):
        """
        Upload a photo to a dataset's gallery.
        """

        simple_upload_url = 'related_tables/%s/upload' % gallery_id
        chunked_upload_url = 'related_tables/%s/chunked_upload' % gallery_id

        data = {'source_amigo_id': source_amigo_id}
        if isinstance(file_obj, basestring):
            data['filename'] = os.path.basename(file_obj)
        else:
            data['filename'] = os.path.basename(file_obj.name)
        if metadata:
            data.update(metadata)

        return self.upload_file(simple_upload_url, chunked_upload_url,
                                file_obj, chunk_size=chunk_size,
                                force_chunked=force_chunked, extra_data=data)