use strict;
use warnings;
use WWW::Mechanize;
use HTTP::Cookies;

my $url = 'http://target-site.com';
my $cookies = HTTP::Cookies->new( file => "cookies.dat" );
my $mech = WWW::Mechanize->new( cookie_jar => $cookies );
$mech->get($url);
my ($button) = $mech->find_all_inputs(
        type  => 'image',
        name_regex => qr/yesButton$/,
);
if (defined $button) {
        print "clicking button...\n";
        $mech->click($button->{name});
        $cookies->save;
}
my $response = $mech->content();