To me, she's not Alix, thought it does look like her..
I don't think that those jewels survived the revolution, nearly none did, no matter who they belonged to.
I am assume that this is the original photo, but scanned?
Because, if you look at her jewelry closely, there is a blue sapphire, and a photo from that era (a sepia photo, no less) would not have any color.
You can see that the diamonds are the color white and gleaming, also.
This photo has been tampered with.
Or am I seeing things?