Ok so I've checked yes I wasn't delusional that picture does exist and is showed in the end to explain some things (but I believe this scene is DLC exclusive?). From what I heard the game does have this weird romantic thing where all girls on the team have a bit of romantic feelings for protagonist while he is completely oblivious about it. But you can get through it if you really want to. But I would still recommend 1 and 3 (Xenoblade X is a spin off from what I heard so it's not really good to start from it either) to start of to understand if you're into it or not. Don't worry other ones don't have weird thing as Xeno2 (⌒∇⌒)