This achievement is earned for finding optional photo #7. 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 #7
In the 5th iteration of the never ending dormitory hallway when you switch from Victoria back to Max you'll be able to photograph giant squirrels outside the windows near the washroom.
Collecting all 10 photos will also reward you with the following achievement: