Here's the new poster, which was unveiled yesterday, in conjunction with an Attack on Titan exhibit in Tokyo:
According to Anime News Network, the colossal Titan in the manga and TV anime was about 60 meters tall (about 200 feet). In contrast, the live-action films' colossal Titan will stand at twice that height, "towering over even the 108-meter (350-foot) height of the tallest movie Godzilla ever, the monster from Garth Edwards and Legendary Pictures' Godzilla film this year."
In other words: This thing puts the Titan that peered over Wall Maria to shame.
ANN translates the poster's taglines:
The world is cruel.
Attack on Summer 2015.