Gill was the first painter[A] – after their rediscovery in 1819 – to make extensive copies of the Buddhist cave paintings, which mostly date to the 5th century CE.

[11][12] From 1844, Gill was taken away from military service to copy the Ajanta murals for the Asiatic Society of Bombay, at an additional salary of 200 rupees a year.

He spent thirty years measuring, mapping, cataloguing, photographing, and painting in the caves, despite dangers from wild animals and the local Bhil people.

The four surviving Gill copies are in the Victoria and Albert Museum in London; a number of his drawings are in the British Library.

According to the Victoria and Albert Museum, even in Gill's time the original cave paintings could be seen suffering damage from frequent, unsupervised visitation and also from "swarms of bees and bats.

"[5] Gill's works also record the condition of the stonework at the time; some sections have since been lost, such as the portico to Cave 1,[17] and others considerably repaired and tidied.

[8] In 2012, a Marathi language film, Ajintha, was made based on his work and love story with a native girl Paro.