Life Is Strange Episode 1

Right after you have taken photo #3 and have unlocked the achievement Processor, walk around to the right side of the diner, and turn left past the homeless person. Once you have done that you should have made it to a fence, and you should see an RV with a guy and a dog sitting outside of it. Look at the dog and you will be prompted to take a photo. Once you have done so the achievement will unlock.