This photo was taken at the Polo Grounds in upper Manhattan on November 21, 1937, as the Packers took on the New York Football Giants.
This was before road jerseys became mandatory, so the Packers wore their new navy jerseys with gold yokes. The Giants rotated between red and royal blue jerseys that season, so it's possible that this might not have been a blue-on-blue matchup.
I love the official's uniform, with its flat cap and very blousy knickers. We can also see his stirrups clearly enough to notice that he's wearing the right one backwards (big hole goes in the back).
They might have looked good, but the Packers lost that day, 10-0.