This achievement is earned for finding optional photo #4. If missed on the first run, you can "Play Episodes" and select specific parts of the Episode in order to find the missing optional photos through collectibles mode
. The following collectible is described and can be seen below:
] - Optional Photo #4
Walk behind the diner to find a homeless women. Continue past her to the fence and take a picture of the dog through the fence.
Collecting all 10 photos will also reward you with the following achievement: