Book 3 really does feel like it is coming a lot sooner than Book 2 took. Bryan on his tumblr page posted  what I believe is our first colour image of Book 3.

Book 3 Lin

He once again confirmed that Lin will be a much bigger player in Book 3 Change than she was in Book 2 Spirits which is exciting.

As for the screenshot, either Lin has just been working out or she has just got up after a nightmare, those are my two guesses.

Also it is a great sign that we are at the stage with Book 3 where we are seeing full colour nearly complete screens. It is probably only about 6-7 months ago where we were at the same stage with Book 2.