May be a fake screenshot, which isn't all that hard to do technically. Pick some existing gameplay footage + edit some parts in/out + open it in image viewer on modded Switch = free Reddit karma. So, I'll recommend taking it with a grain of salt until (and if) the game actually gets leaked or at least receive more actual non-official footage.
There's a bunch more pictures. They don't look fake to me.
http://www.jeuxvideo.com/forums/42-3015138-62396199-1-0-1-0-topic-des-spoils-leaks.htm