Engagement photos, they're there forever, and everyone is going to want to see them, so make them good.
Failing that, make them memorable, like this couple.
They decided to take the piss a bit and make some incredibly awkward ones, which to be fair says a lot more about them than some fake poses with false smiles like we've all seen a million times. Their friend posted the images to Imgur, and they're still up there, so we assume the couple are OK with it.
They seem like good craic.