Holograms are common in the Star Wars universe. The first, or at least the most memorable, being R2's projection of Princess Leia.
Note that this is a scaled version of Leia. Possibly because that took less memory to store, but importantly supporting that holograms can be easily scaled, even by a humble astromech droid.
Then we come to:
My neck hurts just thinking of a helmeted figure craning to look into the eye of that character.
Why did the viewers not scale the hologram to a convenient size?
(And boy, I sure hope the "I am your father!" shock reveal of this trilogy is not "I'm as tall as Yoda!")