1. A method comprising: sensing a user action; in response to the sensed action, capturing first image data, using a first optical portion, from a first side of an apparatus, wherein the first image data depicts a subject; in response to the sensed action, capturing second image data, using a second optical portion, from a second side of the apparatus, wherein the second image data depicts part of the user, wherein the first side of the apparatus is opposite of the second side of the apparatus, wherein the first and second optical portions have parallel but not coincident optical axes, and wherein the capturing of the first image data and the second image data occurs at the same time; computing a hash based at least in part on the second image data; storing information including at least information based on the first image data, and the hash; and consulting database information comprising stored data for plural different persons, to attempt to identify, by reference to the stored information, the user.