With exception of the very few truly artistic photos, almost all photos need extra information, meta data, which can add significantly to the value of the photo. This kind of data can be divided into three levels, physical data, description and context. Of course, these are not always completely separate, and not always equally useful.

Physical data

Physical data is data that tells where, when and how the photo was taken: Geographical location, date and time, camera, lens, shutter speed, aperture, film, ISO and a load of other technical data. Modern digital cameras can embed this information within the photo as you take it.

Time, date and location enables you to order your photos and look up information about the location at a later time, while the photo-technical data allows you to review your skills and maybe get a better shot next time.

Description

The description is what appears in the photo. That is who and what. It may also contain some physical data in a textual form, for example names of places. The description is focused on the moment of the photo.

Context adds information about before and/or after the photo was taken. This is what adds action to your photo: Why where you there, what were you doing, and what happened next. This adds a story to your photo.