This post will be a slight off-topic, but I will continue BlessOTMA's thoughts.
No, really, I have always wondered -- why do the wrong captions appear in Romanov books? Is that because:
1) A writer doesn't think that correct date is sometimes important, so he/she gives an approximate date?
2) Simply the owners of the photos can't remember the date the photo/s was/were taken. For example, Pierre Gilliard's captions are mostly true. Count Grabbe's book contains mislables as well.
3) Something third?
For example, when you search trough GARF's site and when you find any Romanov photo - you will see excellent and precize information on the photos - place and date (if you don't get correct day in a month, then you'll surely get correct month and a year always).
I have noticed that we always have a trouble when identifying the date of the captivity photos taken at Tobolsk; or we are not sure whether one was taken at Polar Star/Standart; or whether we are not sure was the photo taken at Livadia or Finland; remember when we had thought that the photos from Anastasia's album during the war were taken in Peterhof in 1915 while actually it took place at Evpatoria in May of 1916; or whether (NA)OTMAA's formal photos were taken in 1913 or in 1914 at Livadia or at AP. (Luckily, we have got Imperial Family's diary entries so we can get better image). And so on, and so on...
EDIT: Some general/interesting facts on Anna S. Demidova:
1. She played piano and knew several foreign langauges.
2. She became Empress' lady-in-waiting in 1901, after Empress Alexandra had become interested in her needlework at the exhibition of handicraft work at Leushinsky's monastery, Yaroslav.
3. She had got three siblings - two brothers, Aleksandr and Nikolai (typical anmes for Russians Tsars) and a sister, Elizabeth.
4. She had a crush on Sydney Gibbes, OTMAA's royal English teacher, according to GARF.
5. She was cannonized by the Russian Orthodox Church in 1981.
6. She was the only one female servant in Ipatiev House.
7. She visited her home for the last time in 1907.
8. She kept a diary and some diary entries during her imprisonment at Tobolsk are quoted in Romanov books.
9. She signed herself as 'Nyuta' in her letters to her siblings.