the only fake about it , is just a little cut on yoona clothes. the boobs size are still the same.did you realize it ?
It's completely different.
Nope, its called "optical illusion" . Because the upper side of the boobs was revealing, it give you feeling that the boobs are bigger, but actually its just the same. The editor only photoshopped that part, not replace her boobs for someone else boobs.
By the way, I think our current yoona already has a bigger boobs than this one. She is growing now.lol