Phautograph

A term coined from 'photo' + 'autograph', meaning, a photograph which has a signature in it.

Photography literaly means 'light writing'.

In a phautograph, the photographer uses a light to write his / her name, using a technique in which exposures are made usually at night or in a darkened room by moving a hand-held light source.

It will be a mirror image of course, and can be flipped horizontally to be read.