The surest way to avoid ever having your most private photos shared publicly is to not take them in the first place. This is the philosophy behind the most common advice given to teens, among whom the rates of "sexting" continue to rise. Trust no one. Share nothing. Even better: Take nothing. It's ridiculous logic.
Ellen's selfie stunt produced the most retweeted image of all time! Whether you like the fact that it was a staged product placement is not the point because it was brilliant. What I think is even more brilliant was LG's real time content marketing response suggesting a G2 would have enabled Ellen to take the selfie herself.