In the early 1940s, Chang led a group of artists in copying the Buddhist wall paintings in the Mogao and Yulin caves. In order to copy the inner layer of the multilayered murals in the Mogao Caves, Chang removed and damaged several outer layers of the paintings in Cave 108, 130 and 454. Zhang traveled extensively, particularly after the Communist takeover of China in the late 1940s. At this midpoint of his career, Zhang began building an international following, which included Pablo Picasso. In 1943, he exhibited his copies of murals and supported the establishment of the Dunhuang Art Institute, the predecessor of the Dunhuang Research Academy. In 1945, Chang's works, as a part of a UNESCO's touring contemporary art exhibition, were showed in Paris, London, Prague and Geneva.