It is understandable that during the inauguration, President Trump believed he had record attendance numbers -- looking into a crowd gives the illusion of a fuller audience. The problem is you can only see the true size of a crowd from above. What is not understandable is his inability to admit that he was wrong after being presented with the overhead shots from the Washington Monument. His stubbiness to come clean prompted multiple media outlets to file Freedom of Information Act requests for the Nation Parks Service to release their inauguration pictures. These photographs were posted March 3rd and can be found in zipped files here.
The following photograph was taken at 11:56 am. Four minutes before Donald Trump was sworn in. This is a large file, you can zoom in on the monitors and see Justice Thomas swearing in Pence. You will also notice that there aren't many more people streaming in. That's pretty much the crowd for the day.
What is really telling about the expected crowd size is only five of the giant monitors were setup on the Mall for Trump's inauguration. Two additional monitors were setup further back for Obama's crowd plus an eighth monitor for the overflow crowd that was expected (and did) congregating under the Washington Monument. Trump's audience barely made it past the Hirshhorn Museum which was only the halfway mark of Obama's Mall crowd.