Photo credit: RT.com, press TV
Mr. Nasrallah used the recent controversy of the anti-islam film as an opportunity to display his political power by calling for demonstration on September 16, and have them materialize on September 17th. If only Mr. Mousavi wielded the same power in Iran, but that's another story.
It must be said that the Hezbollah demonstration was well organized and PEACEFUL, in contrast to the violent demonstrations led by Sunni fundamentalists in other islamic countries.
The Hezbollah leader used the opportunity to refocus the anger on Israel and the USA, and try to appear to defend the Christians (some of whom are his allies in Lebanon, and others allies of Assad in Syria) from being blamed for the film, which was made by an Arab Christian.
Mr. Nasrallah called for the demonstrations on TV with a different banner in the background. He used a unifying Islamic banner of the prophet behind him, as opposed to the usual sectarian Shiite banners he is more accustomed to using.
With the Hezbollah leader attending in person, despite the risk of assassination by the Israelis, this demonstration went a long way to demonstrate that Hezbollah is still locally powerful, regardless of the survivability of their allies, Iran and Syria--I'm sure by now every political party in Lebanon knows that.
The only open question remaining is if the Saudis are willing to accept the message Hezbollah is trying to convey, and decide not to pursue their long standing efforts to eliminate, or at least weaken Hezbollah by all means necessary. I personally doubt that, as the Saudis seem to be very driven when it comes to sectarian conflicts, and aim to win the sectarian battle in the name of all Sunnis in the region.
I don't know if you knew, but the Hezbollah demonstrations had nothing to do with the anti-Islam movie; just FYI.
Ps. Please note the similarity between the iranian revolutionary guard corps (IRGC) logo, and the Hezbollah's logo.