do you mean like gameplays of the game. like this

you know where you write right? bottom left you see a Album button, Press it to send a picture (from you gamepad or tv but you can only send one of them)

i mean bottom right

It seems that only Wii-U owners can do it (?) but I saw 3DS screenshots before so far, everyone is all of a sudden clueless about that specific topic... (I heard it'll come soon for 3DS) It's all confusing tbh

Yes, they can upload picture when they on a game

i had a 3DS but its broken i remember that i can post picture but i don't know why it say coming soon?