Earlier this week, I watched
Despicable Me 2 (for only the second time), and I noticed a brief visual allusion. Early in the movie, there are some scenes of Gru's lab, and one of them shows a group of minions sitting on a beam and eating lunch:
This seems to be based on the photograph known as Lunch atop a Skyscraper:
According to
this article (which is also my source for the above image), the photograph was taken on 20 September 1932.