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:
[
2:06] - Optional Photo #4
Once you make it outside the dormitories, walk to the far end of the area where you'll notice a girl on a bench in front of a tree. To the side of the tree, you'll spot a squirrel which you'll need to take a photo of.
Collecting all 10 photos will also reward you with the following achievement: