James Fergusson, in his introduction, writes of how Captain Gill was appointed by the East India Company in 1845 to copy the paintings in the Ajanta Caves and records that several of his works were exhibited in the Indian Court of the Crystal Palace at Sydenham. Worswick describes how Gill devoted the rest of his life to documenting the caves, living there with his Indian mistress and working even when ill.
As part of the general trend towards using photography for recording the architectural heritage of the country, Gill was equipped with a camera by the Madras Government during the 1850s. He became a corresponding member of the Bombay Photographic Society after it was established in 1854, and in the spring of 1862 sent 200 stereoscopic views of Indian subjects to London. This selection of "sixty-two ...of the Caves, twenty-four...of Indian structural architecture, and fourteen scenes of the chase" was published. Fergusson concludes "....the Photographs tell their own story far more clearly than any form of words that could be devised, and even without the text they form by far the most perfect and satisfactory illustration of the ancient architecture of India which has yet been presented to the public."

Gill's photographs were used both in the above publication and in The Rock-cut Temples of India, published in the same year.