Today, Nokia’s Kevin Shields demonstrated a feature called Smart Shoot, that will definitely help get rid of those photo bombers that may be infiltrating your attempts of capturing your most precious moments.
When you take a picture using Smart Shoot, the software actually takes several pictures so that it could determine what things in the view are moving. It then presents you with a screen outlining the moving elements. With a touch of an outlined figure the user can remove that element from the image.
This can prove useful when taking a picture in a busy area, where there may be many people walking around in the background. It also can be used to remove an unwanted subject that rushes into the photo in the last second.
Source (Nokia-Microsoft Press Conference)