Al-Áţāyā al-Qadīr fī Ĥukm al-Taşwīr
The Bounties of the All-Powerful: The Ruling about Creating Images of Living Things
Making pictures of living things is forbidden in Islām; suspending images is also forbidden. This is a comprehensive fatwā on making and using images. Alahazrat did not permit images of living things and mentioned a number of ĥadīth that forbid images which includes portraits and photographs. This fatwā is mainly about (analog) photographs, which was still a relatively new phenomenon in the late 19th century.
Note: An Arabic translation is also available.