This achievement is earned for finding optional photo #9. 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 #9
To the right of the diner, you find an alley with a homeless woman. Just before her, you'll see some trash cans, with a dead bird on the ground and a circle of ants around it. Take a picture of this.
Collecting all 10 photos will also reward you with the following achievement: