Check your multiplayer options when you load the game, your default key should be F12 to take a screenshot.

While in game, just press F12 to take the shot, it will end up in one of two places.

If it's a normal server, then C, Program Files, Call of Duty, Main, Screenshots.

If it's on an awe modded server, then C, Program Files, Call of Duty, Awe, Screenshots.

To post it, upload your image to http://www.imageshack.us/ and use the Direct Link to the image, and in your post put:

[*IMG]http://imagelink.jpg[*/IMG] without the *

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