
Calling GDElla!!! I KNOW that you must know the answer to this!
Janet R.
Thanks for the vote of confidence Janet.

I'll have to do some thinking on this one.
Just for some clues:
Peter was born in 1868 and was married to Olga from 1901-1916 (to help date the photo). His female Zarnekau cousins were born in 1883, 1884 and 1892 respectively.
That seems to big an age difference for this photo.
His uncle Nicholas had 1 daughter about the same age as Peter. They were Alexandra, Ctss von Osternburg who was born in 1864. Two other daughters died before 1890.
Peter didn't seem to have too many female cousins around the same age--at least not on his father's side.
On a side note, did Alexandra marry AII and Katia's son George?