Not too funny picture, indeed, but it is definitely humor, reminding popular old joke from USSR times.
Typical situation:
Instead of studying in warm classes, students of my class in school (i.e. школьники) are helping kolkhoz's workers to gather beet crop.
Beet had not grown, it is snowing in September, and there is no hope to get warm in the field. All are in low spirits. Suddenly one guy screams cheerfully:
"Работайте, негры, солнце ещё высоко!"
Isn't it funny