'fraid not.
The photo is misleading.
First, I've been to D.C. rallies. Ron Paul's was held in the same location with a crowd that seemed to fill out most of that area in front of the water (but not as densely, I'll admit.) I thought the crowd was huge but it was later estimated at fewer than 10,000 people. Let's assume due to more efficient seating, Trump had ten times that number in the area before the water. That's still only 100,000 people. If there were another 400,000 behind the water, I'd be very surprised.
Second, you can see in your photo that the crowd ends long before the Washington Monument. The Washington Monument is just HALFWAY to the Lincoln Memorial. In the image below, it's clear that Obama's crowd went much further back - and, no doubt, much further in other directions too.
I believe I've seen photos from Obama's inauguration where the crowd ran a pretty good distance toward the Lincoln Memorial. I haven't been able to find them today, though.
It's obvious to me that threats of rain and violence had an impact on the turnout. I also can't stress enough how extraordinarily liberal the fifty miles surrounding Washington D.C. are. Right there, you have reason enough for Trump to draw lower numbers than Obama. There just aren't that many conservatives living within a short distance.
| 
