The meeting was supposed to be 1 hour and went 1.5 hrs....it is actually possible that they went over time and Trump had to get to his meeting with Ryan.
I guarantee you there were photographs taken because there’s always an official photographer where the president goes.
It is equally possible that one of the Obamas told the other that there’s no way I’m standing there and getting my picture taken with these people
Obama probably didnt like the way he looked in the photos relative to Trump and so wouldn’t allow them to be released.