Behold: Facebook’s Secret Photo Sharing App

Last night, something very interesting came our way. Something massive — documents and images outlining what appears to be a new Facebook iPhone app built around photo sharing. We teased what we had with a single image last night. Now, as promised, here’s the rest.

A few notes: the images we have suggest that while polished, this still may be a work in progress. It’s clear that some of these mock-ups are older than other ones, given a few documents we have as well. Also, some images make it seem as if the service will eventually reside within the existing Facebook iPhone app, while others seem to showcase an entirely new app (or a completely redesigned Facebook app). It’s entirely possible that both will be correct. It would make a lot of sense for Facebook, which is by far the largest photo service on the Internet with close to 100 billion photos, to make their own dedicated photo app. The space is exploding with popularity right now as Instagram and others are gaining millions of users quickly. Regardless, Facebook’s focus on mobile photos going forward is very clear.

It also looks as if at least a part of these apps are using the some HTML similar to what has been recently rolled out to m.facebook.com. This is not surprising. Given their talk of commitment to HTML5, Facebook likely wants to make an app that is as portable as possible. That is, while it may be built first for iOS, it can easily be ported to Android and other platforms with the HTML5 elements in place.

The app seems to be a combination of Instagram, Color, Path, and even Path’s new side project, With. The last two are particularly interesting since those two projects are the work of Dave Morin, the former lead of Facebook’s Platform team. And while Path is tied in closely now with Facebook integration, With went with Twitter. Also worth noting is that Instagram co-founder Kevin Systrom was once approached by Mark Zuckerberg about working at Facebook way back in 2004, after they caught wind of his first take on a photo sharing service. Systrom declined the invitation, and now Zuckerberg is a Instagram user (which also connects to Facebook).

Going back to Twitter, the obvious thing to say here would be that this is in reaction to Apple teaming up with that other social network for iOS 5. But this new Facebook app, which we’ve heard may be internally called “Hovertown” or “WithPeople”, has clearly been in development for quite a while. But it’s also true that Facebook and Apple had been talking about iOS integration at various points (notably for iOS 4, which obviously never happened).

Below, enjoy the full monty. Note the location elements, likes and comments, multi-picture mode, filters, multi-user albums, face-tagging, and more. I hope this app sees the light of day. It looks awesome.

And sorry, Facebook. But consider us even for the Facebook Fax thing. Finally.