I think "selfie" is a useful word, not to be confused with "self-portrait," which is much more general. To my mind, a "selfie" is taken with the simplest of equipment, on the spur of the moment, with the intention of posting it to a "social media" site. Sort of a way to say "Look at me!" for people who have little better to say to the world.
The few "selfies" I've seen tend to be crude and ugly, and involve silly mugging for the camera.
Rembrandt made some lovely etchings of mugging self-portraits, but he didn't have either an I-phone or a Facebook page, poor guy.
I took a snapshot just a couple of days ago of someone making a selfie, out on the rocks at Halibut Point in Rockport, Massachusetts. I haven't seen the selfie that was produced, and I don't think I'd care to either.