H1B- Change of employer

[munna11111]

Hi,
I was working for company A and VISA valid till sep 2015. I have changed employer B got visa extension till jun 2017.

1) Is it mandatory to go to the bio metric before visa interview.
2)If not, do we need upload our photo in DS-160 form.
3) If visa gets rejected, do I need stay back in india?

Thanks in Advance