Are you not entertained?!

[Oberon]

Oh dear, that pic has a myth in it there. The Thumbs down and up gesture.
Generally it was a flat palm or a closed fist.

Contrary to popular belief, the emperor did not give a thumbs up or down for a gladiator as a signal to kill his enemy. The emperor (and only the emperor) would give an open or closed hand – if his palm was flat, it meant “spare his life”, if it was closed, it meant “kill him”. If a gladiator killed his opponent before the emperor gave his permission, the gladiator would be put on trial for murder, as only the emperor had the right to condemn a man to death. In the image above we see this myth in action.

http://listverse.com/2008/05/05/top-...ut-the-romans/