These are the work of the Aaron Sims Company's artists, which gives you the chance to look at the faces of Koba, Caesar, Cornelia, and Maurice. The detail in the faces and eyes are particularly arresting.

Here are the rest of the character concepts, with Cornelia's leaf crown a particular stand out:

They also released key art of apes hunting in the California forests where the film is set:

[Concept Art World via Comic Book Movie]