After winning praise for shooting
The Big Parade (1925), the newly formed studio's
first smash hit, Arnold was chosen to head of MGM's camera department.
From 1931-1956 Arnold was responsible for assigning cinematographers to
match the demands of each production assignment; an enormous
responsibility when one considers the 50+ feature release schedules
along with dozens of short subjects produced on the lot annually. He
was also responsible for keeping MGM's equipment up-to-date and
operational (overseeing the studio's repair shop), along with selection
of film stock and lenses.