if ( $TEST_GD ) {
    open my $fh, '>', 'gd.gif';
    binmode $fh;
    print $fh join '', @data;
    close $fh;
}
else {
    Imager->write_multi({
      file => 'im.gif', type => 'gif', gif_loop => 0, gif_delay => 1,
    }, map { Imager->new(data => \$_) } @data) or die Imager->errstr;
}

__END__

319 frame GIF done!
compute time: 11.765s
Total: 12.015s