It's not clear what you're doing with both @pictures and $picture. You should remove the line that is marked broken, and change the loop over the pictures to:

sub make_barn
        {
        my($barns_path);
        my($picture);
        my($barn_number, @barns);
        my($barn, $member);
                
        $barns_path = './barns';
        
        $barn = Archive::Zip->new();
        
        foreach $picture (@_)
                {
                $member = $barn->addFile($picture);
                $member->desiredCompressionLevel(9);
                print "Added $picture\n";
                }
[download]

And you've made a very good decision to use Archive::Zip :-)