From Yakovlev's 1928 description of the Little Pair's bedroom:
In a closet at the back wall the childhood belongings of the princesses are stored, such as: dresses, coats, umbrellas, shoes, baptismal bonnets, hats, knitted blouses and so on. Based on that information, I believe this photo, which has been labeled as Olga and Tatiana's bedroom, is in fact the rear wall of
Maria and Anastasia's bedroom:
Olga and Tatiana's bedroom had a similar set of doors at the rear of their room, but those doors led out into the central corridor. You can see them in this photo of Maria and Nicholas in 1917:
The nearly identical style and position of the iconostases in each corner has probably duped us into thinking these two photos are the same room, but as you can see, the panels of the doors to the left of each iconostasis don't match -- they can't be the same doors. In the Little Pair's bedroom there's even a cot blocking the cabinet doors -- something you probably wouldn't do if you had a doorway leading out into the hallway. In fact, the Little Pair's bedroom had no access to the central corridor: