The Tytlers were introduced to photography by Felix Beato and Dr John Murray of Agra. In May 1857 the couple were resident in the military cantonments outside Delhi, where Robert Tytler's regiment, the 38th Bengal Native Infantry was one of the first to mutiny during the great rebellion of that year. Because she was heavily pregnant, Harriet was allowed to stay on and was the only British woman present at the Siege of Delhi. She later gave birth in a donkey cart while escaping to safer areas. They named this third child named Stanley Delhi-Force Tytler. From 1862 to 1864 she lived in the Andaman Islands where her husband was posted as a Superintendent of the Penal Settlement (which was established mainly to house prisoners from the 1857 uprising). The region around a 1100 foot high hill in the South Andamans, which was named after her as Mt. Harriet, was cleared of forest by Tytler. The area is now protected as the Mount Harriet National Park. Tytler's tenure in the Andamans was short and they moved to Simla. In Simla, Harriet founded an Asiatic Christian Orphanage.