Selfie

A photograph of you taken by yourself, usually for use in social media (noun [countable] informal):

'If cinema was the great art form of the 20th century, the selfie (a self-portrait uploaded to social media sites) will stand as the pinnacle of creative expression in the 21st.'
New York Daily News 10th April 2013

'He's noticed that when he doesn't post a selfie, his followers go down by fifty a day. A lot of people are following him because of the selfies.'
Courier Mail [Australia] 15th April 2013
 

Background – selfie

The term selfie, sometimes though less commonly spelt selfy, first emerged in 2004 as a catchy Internet abbreviation of the word self-portrait. It was initially used as a hashtag on photo-sharing sites to indicate that the subject of a photo was the person who had uploaded it, but gradually began to take on a life of its own as a general reference to a self-taken digital photo.

Selfie/selfy is a recent example of the use of suffix -ie/-y to form diminutive nouns and pet names (compare, e.g. kid > kiddie, television > telly, Bill > Billy, etc). The same process also features in lappy, a newly coined reference to laptop, though this has so far been slower to catch on. In British English, use of -ie/-y generally has affectionate overtones, and its adoption in selfie could perhaps have been inspired by observing that it often features in 'guilty pleasures' or indulgences, as in e.g. choccy, biccy, drinkies, etc.
Source: MacMillan Dictionary Buzzword