You don't know how to make a screenshot?
!!!WARNING!!!
These screenshots are applicable for submitting of bugs, glitches, or inappropriate sprays. The chat logs are acceptable!
Don't says we didn't warns you!
During the game, press F5ONCE and minimize the game.
Go to your steam folder (Default for 32bit OS):
C:\Program Files\Steam\steamapps\youraccountname\half-life 2 deathmatch\hl2mp\screenshots
Go to your steam folder (Default for 64bit OS):
C:\Program Files(x86)\Steam\steamapps\youraccountname\half-life 2 deathmatch\hl2mp\screenshots
now, you can upload the picture to image hosting website, such as imageshack, photobucket, tinypic and many more; after that, you can post it on the forum and open it for discussion.
You may or may not need to editing the photo, the picture is already in excellent quality for everyone to see. There's only difference on that is depending on what screen resolution you are running on HL2DM, such as 1440x900, 1280x720 and so forth.
^COMMODORE64