One Hour Photo Ending Theories [Discussion]

I just watched One Hour Photo (2002, pretty old I know) starring Robin Williams and it was a great film. I just noticed something strange at the end of the film and tried to speculate what really happened.

I believe, the entire sequence where Sy barges in to room 511 (Where William Yorkin the husband, is having an affair with Maya Burson) was just all Sy's delusions.

[Pictures, proof, and my thoughts on the album linked above.

TL;DR: There should have been pictures of the affair on Sy's cameras, but as seen at the end when the detective gave Sy the processed pictures from his cameras (the one left at the hotel room and the one on his bag) there were only pictures of the mundane things in his hotel room]

What are your thoughts on this?

edit: If these speculations are true, it changes the character of Sy greatly. Yes he's still a psychopath (probably due to the childhood trauma his father/mother did to him alluded in the final scene with the detective where he talked about William Yorkin not being a good father). but he never intended to hurt anyone, he never intended to do things he did with William and Maya during his delusions because he knew the pain, the trauma it causes because he'd already lived it and wanted no one else to lived through the same pain. He just wanted to fix the Yorkin family because the Yorkin family was his ideal family, family he never had; and in his deepest darkest dreams he just wanted to be a part of that family.