http://dyn.u13.net:6080/stats/6822.php

How do I get one of those?

Those are stats only from players that have been playing on U13.
If you want to appear in those stats you'll have to play on the server and after some time you'll be able to view your own statistics:
http://dyn.u13.net:6080/
Otherwise there's no simple way to create such an image.

by 'some time' he means at most a couple hours