That picture was taken hours before the inauguration.
By 12 noon, the Mall was packed all the way to the Washington Monument.
Additionally, this year security required the entire Mall be fenced, with only a few understaffed access portals. Obama had free and open access in 2009, with no fences and security portals.
Also, no official entity makes crowd estimates on these kinds of events. They gave it up years ago because the estimates were inaccurate and used for political purposes.
The Park Police don’t; the Metropolitan Police don’t; the Capitol police don’t.
Here is an example of what a true analysis might reveal on Mall crowd estimates, done after the Tea Party rally in 2009: http://humanevents.com/2009/09/16/numbers-game-how-many-really-attended-the-sep-12-rally/
Yes, this is what I’ve been trying to say, there was no open access. This time people had to filter through a couple of check points which caused a bottle neck into see the inauguration speech. By the time the ceremony was in full swing more and more people were filtering in and by the end it was filled. It is important to combat the leftwing lies.