Hmmm... what's the best word to say when taking a photo?

Any idea what it is? Well, you can say "cheese", "karma" or "cheers" if that's the way with you.
But what comes of you when you say:
Cheese------- Gives you the best smile you can ever have!
Karma------- Weird smile... looks like a lunatic, seriously.
Cheers------- Murderous smile, had better not look too suspicious.