Ok So I checked it out and as it looks blank from that distance its hard to tell, I will say that he did sign real documented bills that day so what the problem? I'm confused, so they use a default blank bill to pose for a picture and somehow he is a liar?
How did he lie? its just an appearance photo.
So if you do a photo next time remember, even if it's just for appearances, everything has to be 100 percent honest and truthful, even a blank piece of paper is wrong.
Its called a staged photo appearance, there very common and every president had made them.