The Aeris's Face on the sign

From FF7Citadel:

http://www.ff7citadel.com/secrets/s_...ovelessac2.jpg
The Zack's ghost appeared in the photo. O_O

From Squall of Seed:

http://img.photobucket.com/albums/v1...hotographs.jpg

What I don't get is why didn't Aeris appear in that photo too?
And a poster of FF7 behind the wall in the beginning but can't find the picture of it.

There's probably more, we should control frame to frame if we became suspicious, there's a chance that SE had added more something that are hidden :P