Studium
Barthes's term for the general, culturally shared interest a photograph holds — its subject, context and craft.
In depth
The studium is what can be discussed: the historical situation, the technique, the photographer's evident intention. It engages the viewer politely and predictably, and Barthes contrasts it with the punctum precisely because a picture can be entirely competent at the level of studium and still fail to move anyone.
Examples in practice
Recognising a photograph's period, place and technical accomplishment is engagement at the level of studium.