The outcome of taking a Selfie during, or shortly after getting swole at the gym.
Dude, did you see bill at the gym?
Yeah I did. He was taking a swellfie in the locker room
To take a "selfie" after you've hit the gym and you're swollen. Normally posted to Instagram or Twitter or sent in a Snapchat, to make yourself appear to be bigger than you actually are. Mainly taken by "bros", and insecure people who need others to reassure them that they are the most muscular douchebag around.
I looked like a total douche taking a swellfie in the locker room but the girls on Instagram will love it.