People In Portraits By Bernd Opitz

As photographic techniques developed, an intrepid group of photographers took their talents out of the studio and onto battlefields, across oceans and into remote wilderness. William Shew's Daguerreotype Saloon, Roger Fenton's Photographic Van and Mathew Brady's What-is-it? wagon set the standards for making portraits and other photographs in the field.
Politics
In politics, portraits of the leader are often used as a symbol of the state. In most countries it is common protocol for a portrait of the head of state to appear in important government buildings. Excessive use of a leader's portrait, such as that done of Joseph Stalin, Adolf Hitler, or Mao Zedong, can be indicative of a personality cult.