Google has inadvertently released what appears to be a partially-finished iOS application to Apple's App Store, leveraging its new Chromecast television dongle peripheral. The new iOS-only app called "Photowall for Chromecast"
will at some point allow users to create a photo montage through the iOS device to a Chromecast.
Photowall for Chromecast allows users to take a picture, and send it to the device for display. Multiple users should be able to connect, according to the app description, making the app collaborative. Following completion, it will then automatically generate a YouTue video, viewable by all.
The app allows you to connect to Google+, but doesn't proceed past a blank page with a password field. It appears that the App has been made available prior to Google's full implementation on its end.