use strict;
use warnings;
use feature 'say';
use GD;
use Digest::MD5 'md5_hex';

say $^V; 
say $GD::VERSION;

my $f = 'frog.png';

GD::Image-> trueColor( 1 );
my $i = GD::Image-> new( $f );
say "Image is ", ( $i-> isTrueColor ? '' : 'not ' ), 'truecolor';

say md5_hex( $i-> png() );

__END__

v5.32.1
2.76
Image is truecolor
1b6edecaa6d0b67f7bf960113f2136c7

v5.16.3
2.49
Image is truecolor
9edf3f9e11991f2dcfd77a7e1ffbafe8