This achievement is earned for finding optional photo #6. 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 #6
After getting dressed, and exiting Chloe's room, go the washroom (not downstairs), and take a selfie in the mirror.
Collecting all 10 photos will also reward you with the following achievement: