At the end of the tanker chapter you should be able to access Otacon's computer program to send images. You are supposed to send pictures of Metal Gear, but there are others you can send as well and get a special reaction from as well. If you constantly send these photos over and over again, he will have different reactions to them, some are abseloutly hilarious. These are two and what he says:

1. The Vulcan Raven figure in the engine room entrance: Snap a picture for all the slots and get to the computer. He will tell you that he can save it for you in the future.

2. The Comandant who is saying the speech: This is better because you can take as many as you want. After about 7-10 of these his cartoon will be in tears saying that you better stop because you're freaking him out.