Your pictures show the 9-12 rally as exceeding the inauguration and similar to the 1997 "Stand in the Gap" rally by Promise Keepers, which hit about a million.
The count doesn't matter; the fact is, America showed up in Washington D.C., that we're aware, we care, and we're watching our representatives. They'd better not harm us any more than they have already--the next march might have more, and be more hostile.
Practically, if every attendee got 50 people to vote out "bad" incumbents (those who supported Obamacare, for example), then we'd clean House, and maybe a 1/3 of the Senate in 2010.