can't render?

hi all.
i used the Node editor for the first time today, and i got the result i wanted out of it but it won’t let me render it. it says there’s no render output in nodes scene. it’s probably a dumb question to ask, but like i said, i’ve never used this before.
here’s a screen capture:

Add a Composite Node. (Shift+A - Output - Composite). Whatever is plugged into that is rendered in the final image.

awsome! thanks!