I am looking at the photograph on the cover of Tom Overton’s “John Berger: From Life,” the second biography of the British art critic and novelist that Verso Books has published since his death, in 2017. The first, Joshua Sperling’s “A Writer of Our Time” (2018), was a brisk study that appraised Berger as a leftist popularizer of the Western tradition in art. Berger made his reputation as a critic by the age of twenty-five, asserting himself in contrast to the patrician figures of his era.