open my $fh, '>', 'data';
binmode $fh;
print $fh pack 'C*', @data;
close $fh;

`convert -depth 8 -size 256x256+0 gray:data data.png`;

##</code><code>##

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