load your map
open the console (~ tilde key)
bind a key to the screenshot command
/bind F12 screenshot
close the console
hit the F12 key. A .tga file will be created.
If you bind the screenshotJPEG command to a key you will create a JPEG instead of a TGA file.
screenshot : save current viewport to a TARGA image file (usually named sequentially shot0001.tga)
screenshotJPEG : save current viewport to a JPEG image file (usually named sequentially shot0001.jpg)
See Commander Keen's Quake3 Arena Console Page
for a complete list of Variables, Commands and Tweaking.
Never give in--never, never, never, never, in nothing great or small, large or petty, never give in except to convictions of honour and good sense. Never yield to force; never yield to the apparently overwhelming might of the enemy.
Winston Churchill, 1941.