Haha this would be ironic if Jericho, player who said trophying on HI does not count, trophied playing Manhunt. How is this even comped? You should have some pride and self-suspend yourself from comp :D
But no, there is no way without blocking your browser loading images so it can't load, so it won't send information to that hidden link. That's because messages are stored in a database, and javascript fetchs the message from there, and it triggers when you send a GET message to get the data after you send the cookies(which keeps you online). Your browser loads the hidden image.
Alternatively, if you are good at coding, simply make a bot that fetchs the messages. That way you'll get the raw data of the message.