“If you don’t control your mind,” reads one of Barbara Kruger’s artworks, “someone else will.” (The words are pasted over a portrait of Adolf Hitler.) Control is the theme of this year’s Format 21, the U.K.’s leading contemporary photography festival, and it sees newcomers and veterans alike exploring the ins and outs of control. All forms of photography are included: documentary, conceptual work, even smartphone imagery. Spread across 30 buildings in Derby, there will be events, talks, performances, and master classes for aspiring talents. For those who can’t make it to Derby, Format is also available online. —E.C.