Facebook brought a few modest upgrades to its latest iPhone app over the weekend including the ability to watch videos, read and write comments about events, and post higher-resolution photos.

The app has an astounding 54.8 million monthly active users, which probably makes it the strongest source of mobile use for the social network.  In February, Facebook said it had 100 million monthly active users through mobile phones.

Facebook’s iPhone app has had the ability to post video for about a year, but hasn’t offered video viewing until now. The social network is quickly becoming a power in video consumption with 2 billion videos watched each month. Photos that are posted through the app can also have richer resolution now. They can be 720 pixels wide.

The app’s original developer, Joe Hewitt, who came to the social network via Parakey, its very first acquisition, dropped out of the project last November. It has since been taken over by Owen Yamauchi, who worked briefly at Apple before joining Facebook, and Jeff Verkoeyen, who was an intern for the social network according to their LinkedIn profiles.

There’s no word on when the social network’s much-awaited Facebook iPad app will come. We hear it will reveal several clues to the future direction of Facebook’s interface design.