use strict;
use warnings;
use feature 'say';
use Data::Dump 'dd';
use Imager;

my $i = Imager-> new( file => 'rose.png' );
my $w = $i-> getwidth;

my $m = Imager::transform2( { 
    rpnexpr => << 'END'
        x y getp1 !pix 
        @pix red 128 le 
        @pix blue 128 le 
        and 
        255 0 if 
        0 0 rgb
END
}, $i )-> convert( preset => 'red' );

$m-> write( data => \my $data, type => 'raw' );
$data =~ tr/\0\377/01/;
say for unpack "(a$w)*", $data;

__END__

11111111111111000000000011111100111
11111111111111000000000011111110111
11111111111111100000100001111110001
11111111111111110011011001111111111
11111111111110000000010000000110001
11111111111100000000000000000000000
11110001111000000000000000000000000
11110000000000000000000000000000000
11111000000000000000000000000000000
11111100000000000000000000000011100
11111100000000000000000000000010100
11110000000000000000000000000111111
11100000100000000000000000000111111
11100001100000000000000000001101111
11100001100000000000000000011011111
11111111000000000000000000011111111
11111111000000000000000010011111111
11111111100000001011001110011111111
11111100111000000011111110111111111
11111000010000000111111111111111111
11111000000000000111111111111111111
11111000000000000111111111111111111
11111000000000000011111111111111111