(Last Updated On June 25, 2022)
Three by Leopold Graf von Kalckreuth, including an image from Jugend:

Leopold Graf von Kalckreuth – Brother and Sister Playing Music

Leopold Graf von Kalckreuth – Mädchen

Leopold Graf von Kalckreuth – Kinderbildniss – Jugend No. 9 (1901)
Wikipedia: Leopold Graf von Kalckreuth