You're looking at Camera Extension: a new app for the Lumia 900 that, er, extends the phone's camera function by adding burst, timer and panorama modes plus, most notably, a smart group shot feature. The latter takes five pictures in five seconds, then cuts out the heads and lets you swap 'em out in the same way that BB 10's Timeline Lens (amongst others) works. Will the app bring you out in goofy smiles? Find out in the video after the break, where WeLoveWindowsPhone.hk gives it a go.Cont