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.
A photograph of oneself or a group including oneself that features any type of shell, including seashells and turtle shellsA photograph of oneself or a group including oneself that features any type of shell, including seashells and turtle shells
"Hey Jim, thats a cool shell over there, lets take a shellfie with it."
"Good idea Bob."