Introduction to rock paintings: Drepung Monastery has many rituals. Corresponding rituals must be held on every major Buddhist anniversary and on auspicious days such as Wanghui Day (i.e. the 15th and 30th) of every month in the Tibetan calendar. There are also some activities for monks and laypeople to celebrate together, the most spectacular of which is the "Drebung Shoton". "Shoton" means "yoghurt feast" in Tibetan, and was originally a purely religious activity. According to the laws and precepts of Buddhism, there are "summer residences" where no one can go out for dozens of days in the summer until the ban is lifted. On the day when the ban is lifted, the common people give alms with yogurt. Later, the content of "Shoton" became more abundant, religious activities and cultural entertainment activities were combined, and the scale continued to expand. On the day of the Shoton Festival, which falls on June 30th in the Tibetan calendar, firstly, with Drepung Monastery as the center, a huge Thangka painting of Buddha statues will be exhibited in the early morning, followed by a Tibetan opera performance, which is actually a festival for monks and laypeople to enjoy together.