Why are you necroing? This thread is 4 months old.
Though for reference, the commands are '/screenshot' for a TGA without the UI, and '/screenshot_ui' for one with the UI.
Zombies are one of my least favorite species of the Galaxy. I must destroy this one and remind you Humans to open a new thread if you need to post on a topic that has not seen the light of day in over 30 days.