These pictures were taken in a corridor or series of adjacent rooms, number 11 on the ground plan, where there were several graves on either side with extensive frescoes.
I have been informed by knowledgeable viewer Gerard Vroeijenstijn (whom I thank; translation mine) this fresco represents an act of charity by St. Nicolaus. Nicolaus throws a nugget of gold, wrapped in a cloth into the house of an impoverished nobleman who, driven by great poverty, planned to deliver his daughter into prostitution. Nicolaus knows this and by throwing in gold threefold saves the soul and body of the girls. The three daughters are in the left hand upper part, to the left under the poor and sickly man. The story has inspired countless artists. Several readings of the story exist.