Well i don't kno wif it is from the end of the movie, or the begining, it's just a pic so anything can happen, it could be something they scrapped for all we know.
But if you look behind the Predators arm, it looks like there are to more Preds behind him.
And the PredAlien is injured on his chest.
Now i know the RAIN makes it seem like it's outside, but it could just be that they are on a ship, and it set fire from the predAliens destruction, and sprinklers were set to put out the fire, like in any place you go that has sprinklers on the roof in case of fire.
So it's just a guess, but MAYBE they are on the ship?