N-400 application photographs question.

[Kami]

I'm really confuse about where to sign my name. Do I sign my name in the front or the back of the photo before I mail it to USCIS or I only write down the A# and wait till the interview to sign my name?
But I am still confuse where do I sign it, I have founded two answer:
1) sign in the back with the A#
2) sign in the front in the margin space.
What does it mean by sign in the margin area? The only white space I have in the front is the background(white) color.

 

[Jackolantern]

Don't sign the photographs now. Follow the N-400 instructions, which say "Using pencil or felt pen, lightly print your name and Alien Registration Number (A-Number) on the back of each photo."

At the interview, that is when they may ask you to sign a photograph, and they will tell you where to sign.