The three paintings on the predella of the Perugia Triptych depict the story of St Nicholas.
This is a detail of the right side of the third painting, the death of the saint. According to the Golden Legend's account of this death, there sprang out from under Nicholas' tomb a fountain of oil which was able to cure the sick. The man on crutches on the right may possibly represent those who came to be cured.
Also available: the first and second predella paintings.
More of St.