my $img = Imager->new(
    type  => 'raw',
    xsize => 256,
    ysize => 256,
    data  => pack('C*', @data),
    raw_interleave    => 0,
    raw_datachannels  => 1,
    raw_storechannels => 1
);
$img->write(file=>'data.png');