This is yet another miracle tale from the 觀世音菩薩感應事跡實錄- A true record of A True Record of Guanyin's Response and Effect .https://book.bfnn.org/books/0530.htm.
This miracle tale is somewhat notable as it involves a piece of 'western' optical technology: buddhist rosaries with microscopic images of buddhas embedded in them, that could be viewed with an inbuilt magnifier.
◎玉枝居士，住臺中市北屯區軍功寮。民國四十二年加入蓮社彌陀班，朝暮念佛及觀音聖號。四歲幼弟在附近魚池邊遊玩，不慎落水，池深丈餘，忽一女人跳入水中，抱放池邊，並送回家，女忽不見。 Householder Yuzhi, lived in Jun’gongliao, in Beitun district, Taizhong. In the 42nd year of the Republic [1953], she entered [the] Lotus-society’s Amida-class 蓮社彌陀班, and she chanted the name of the Buddha [Amida] and Guanyin morning and evening. Her four-year-old younger brother was playing close to the edge of a fishpond, when she accidentally slipped into the water, which was several fathoms deep. Suddenly a woman jumped into the water, dragged him to the shore, and sent her home.
其母見子全身濕透，如落湯雞，問明情形，為換衣服後，帶往池邊，水尚未乾，遍詢各家，均不知救水之人。 When the child’s mother saw her child soaked to the bone, like a chicken drowned in soup, she asked what happened. After changing his clothes, she brought him to the pool. The water [splashed around the poolside] had yet to dry. She asked everyone in the vicinity of the pool who saved him, but not one of them knew how to save the drowning.
後買一日製念佛珠頭，內有觀音聖像一尊，全家爭看，弟一看時，即雀躍大叫：「前從池中抱我起來的就是她。」眾始大悟，深感慈恩。 Later, they bought a Japanese-made rosary. Inside the rosary was a small image of Guanyin. Everyone fought to take a look at it.* When her little brother looked, he jumped with joy and shouted “That’s the lady who pulled me out of the pool!” Everyone was astonished, and felt a deep sense of gratitude to Guanyin.
*Ed: this is probably a reference to ‘stanhopes’- tiny photographs that could be viewed through an inbuilt lens. These are small enough to insert into beads.
因他的父母及姊常念觀音聖號，所以落水獲救，凡有子女從軍或外出危險者，請即供奉觀音，禮念觀音聖號，決蒙護佑，永保平安。 Because his parents and sister often chanted the holy name of guanyin, that is why she came to save him when he fell into the water. If there are any people whose sons and daughters are in the army, or travelling to dangerous places, let them venerate Guanyin, chant the holy name of Guanyin. She will definitely protect them, and ever preserve tranquility.