If I post a picture of myself but it was taken by someone else...
@ElectricKeet A photo you take of yourself while holding the camera is a selfie.
A photo taken of you while you are not holding the camera is a portrait. 
@mawr See, that's what I thought, but it seems the other usage is a thing? It's why I put the poll up. :)
@ElectricKeet @mawr selfie is short hand for self portrait, if you didn't create it, then it isn't.
The only caveat I would give is if a person doing a selfie includes you in their photo, because either of you could have taken it.
@AnneDee @ElectricKeet The way language changes over time is often messy, illogical, and frustrating 
@mawr @ElectricKeet and mostly due to the unknowledgeable (i nearly put uneducated, then remembered I know someone with a PhD who thought France was part of the UK).
@ElectricKeet @mawr how? Unless we are dropping photo/photograph from the English language??
If you're in it it's a selfie?
I'm in photos taken by the press. They aren't selfies.