photo (n.)

1860, a colloquial shortening of photograph. The verb is by 1865, from the noun. Photo-finish, of a race that ends with two or more competitors crossing the finishing line at nearly the same time (so a photograph taken at the finish line at the moment of crossing is the only way to determine who won) is attested from 1936. Photo opportunity "arranged opportunity to take a photograph of a notable person or event" is from 1974, said to be a coinage of the Nixon Administration.