What do you mean by “big”. Do you mean he looked taller than in real life? I didn’t notice him looking unusually big. He looked about the same to me as he did in Avengers Age of Ultron and in this set picture from Black Panther. But certainly it’s not a new thing to use camera angles and perspective to make actors look a bit bigger and taller than they are in real life. I couldn’t image that they did anything digital to him.