This couldn't be an Upper Deck, or a Donruss, or a Fleer . . .

. . . it could only be Topps. Rey Sanchez's 1994 Topps card shows him holding his 1993 Topps card.
I wonder if a Topps photographer gave him the card to pose with, or if he saw the card while signing, knew there was a photographer watching, and came up with the idea himself. If that is the case, I wonder if Sanchez knew it was a Topps photographer, or was it a freelancer who decided to send the photo to Topps?