You wanna see what it means by editing the selfie before its taken.
The Genie explains the rules
All you have to is pick what setting you want point the device in the general direction of phone or camera and the next picture that is taken by that device will have your settings applied to it, and not just the picture but also the person.
As for the settings you got a lot of options you can change or remove clothes, add things that weren't there before, and even alter their body itself. Also you can keep them from being able to notice the changes until certain conditions are met like not until they post or sent the picture or until a set amount of time has past.
Not sure exactly what meant by all that the genie gives you an example.
"Look lets say you set someone's phone to make their clothes disappear and that they won't notice for an hour. Unless someone points out to them their clothes are gone they won't notice until an hour later. Okay? Okay. Now lets do this."