Haha - nothing really special. Just in anime, there are moments where they black out the character except for their outfit and hair. It's the
faceless masses trope (TVtropes link warning - the reference images are under "Minami-Ke". They also do that in "daydream" sequences sometimes. I cannot for the life of me find a screengrab example, though.
Anyway - I guess I sort of was going that direction of, "just a daydream sequence" or "just a background character" and it looked creepy enough I kept pushing. So maybe this is a flashback of some tragic anime story and/or this girl is now a ghost.
(Which utterly terrifies me, of course. Shadow people are scary as hell and I have seen them and brrr. But I'm perfectly willing to troll myself sometimes. >_>; )
/ramble