A new mobile photo-sharing app is being tested by Google, which is called Pool Party. This is basically an Instagram rival from Google and it has been developed by the Slide team, which was bought by Google some time ago.
The same team within Google had earlier come up with Disco, which was a group Messaging app. Pool Party is currently being beta tested, and users can gain entry through invite only. The app has some differences with Instagram which is mostly for individuals whereas Pool Party encourages group-sharing.