If you doubt the authenticity of the photo why don't you contact Bp. Williamson and ask him whether or not it is an accurate representation of him holding up the book at the conference's podium? Short of that, you could always buy the DVD of the talk sold by AFP and look for yourself.
Although I did not take the photo, I saw it after it was developed by a professional developer and I vouch for its authenticity. Unfortunately, it is not that clear because it was taken from a good distance with a cheap throw away camera.
James Phillips