4 0 0The achievement seems self-explanatory, but it's worth noting here that if you miss any of the photos, you can still get them by replaying segments of the episodes, an option at the main menu, in "collectible mode." You also have the option to replay the story from whatever point you choose to pick up the photos and redo your choices.
0 0 0There are 10 optional photos to find and take in order to obtain this achievement. You can replay specific parts of the episode in order to find the missing optional photos through collectibles mode.The optional photo locations on this video guide: