Let's play with G6_GRAPH.BIN!

g6.pl

# Extract/import database entries from G6_GRAPH.BIN database
# The Lemon Man (C) 2014

use strict;
use warnings;
use File::Slurp;
use JSON qw(from_json to_json);

sub json_to_db ($) {
    my $text = read_file shift;
    my %db = %{from_json ($text)};
    my @off_tab = ();
    my $off_pos = 0;
    my $thumb_buf = "";

    foreach my $code (keys %db) {
        my $thumb = read_file($db{$code}{'thumb'}, { binmode => ':raw' });
        push @off_tab, ($off_pos, length $thumb);
        $off_pos += length $thumb;
        $thumb_buf .= $thumb;
    }

    my $out .= pack 'n', scalar keys %db;
    foreach my $code (keys %db) {
        $out .= pack 'A[4]A[12]NNn', 
        $code, $db{$code}{'title'}, 
        shift @off_tab, shift @off_tab,
        $db{$code}{'unk18'};
    }
    $out .= $thumb_buf;
}

sub db_to_json ($$) {
    my ($path, $extract_thumbnail) = @_;

    open (my $fd, $path) or die "open";
    binmode $fd;

    my %db = ();
    my $buf = "";

    read $fd, $buf, 2;
    my $count = unpack 'n', $buf;

    my $dupe = 0;

    for my $i (0 .. $count - 1) {
        read $fd, $buf, 26;
        my ($code, $title, $offset, $size, $unk_18) = unpack 'A[4]A[12]NNn', $buf;

        do { $dupe++; } if exists $db{$code};

        $db{$code} = {
            'title' => $title,
            'thumb' => "$code.bmp",
            'unk18' => $unk_18
        };

        if ($extract_thumbnail) {
            my $pos = tell $fd;
            my $buf = "";

            seek $fd, $offset, 0;
            read $fd, $buf, $size;
            seek $fd, $pos, 0;

            write_file "$code.bmp", { binmode => 'raw' }, $buf;
        }
    }

    print "$dupe/$count entries were duplicated.\n";

    my $json_db = to_json \%db, { pretty => 1 };
    close $fd;

    return $json_db;
}

die "Usage : $0 [-j | -d] <file>" if $#ARGV != 1;

db_to_json $ARGV[1], 1 if $ARGV[0] eq '-d';
json_to_db $ARGV[1] if $ARGV[0] eq '-j';