I am not denying the existence of the lawn chair, I am denying that it is my room, or even the room that I am in right now.
It was not my lawn chair, it was not my room.
Notice every time I said "The room I am in" not "The room I was in" thus referring to the present and not the past for if there are any lawn chairs in the room that i am in this very split second.
There is a clear distinction between a chair and a room, should you care to look that up.
TL:DR
There was a lawn chair in the room that I was in for that photo. There is no lawn chair in the room I am currently in (nor has there ever been). The photo taken displays a lawn chair that is not mine, and is taken in a room that was not mine. English is hard?