Context manager to create temporary files and remove them after use.

def _temporary_filenames(total):
    """Context manager to create temporary files and remove them after use."""
    temp_files = [_get_temporary_filename('optimage-') for i in range(total)]
    yield temp_files
    for temp_file in temp_files:
        try:
            os.remove(temp_file)
        except OSError:
            # Continue in case we could not remove the file. One reason is that
            # the fail was never created.
            pass