Update: Empire has posted clearer images of the same photos which I swapped out below. They also provide some more tidbits including full names for some of the characters and plot details.
This fourth film in the franchise is something of a fresh start, and sees an Earth scarred by the events of the last three films but moving on after the disappearance of all giant robots.
When Mark Wahlberg's inventor, Cade Yeager, discovers a buried Transformer, the stage is set for the return of the giant beasties. There will also be some business with Cade's daughter Tessa (Nicola Peltz); her secret racing driver boyfriend Shane; Stanley Tucci's Joshua; his geologist assistant Darcy (Sophia Myles); "the CEO of the Chinese Transformers", played by Li Bingbing; and Kelsey Grammer's Harold Attinger, the film's non-robot big bad.