I don’t know; I’m not a crowd estimator. It looks like a lot people to me.
More important, I think you forgot to add the link to the ABC News 2 million people crowd estimate.
No way are these numbers accurate. There’s some sort of coordinated misinformation from one side or another. 1 of every 150 Americans was in DC for this? I hope the numbers are accurate, but without further verification I’l remain quite skeptical.