Learn English – Antonym of selfie

try antithesis

1. Direct contrast; opposition.
2. The direct or exact opposite

The few sources out there seem to prefer the term "X" Selfie, where X is replaced by family, group, etc.

Unfortunately, there does not seem to be any real consensus, except that a true selfie is more of a snapshot than an artful application. There are some who would claim a selfie must be taken at arms length and not with a mirror or self-timer, but this remains a matter of debate (see comments below!)

Perhaps, the more important distinction falls between a self-portrait vs. a selfie. A self-portrait in most usage implies forethought and artfulness. A selfie is an attempt to record oneself in a place or time. In theory, you could make an artful selfie, but you'd be plundering the territory of self-portraits.

Interestingly, Canon, the camera manufacturer does even not have a terminology for the usage of a self-timer to take a group photo. They refer to using the self-timer to take "self-portraits or pictures of you with friends and family".

Here is the source speaking about the self-timer function in their cameras.