Documenting sources for images can be challenging, especially with the variety of new electronic resources now available. Many different style manuals exist. Always ask your class instructor for the style appropriate for the course.
The basic information you will need:
Title of the work
Date it was created
Repository, museum, or owner (in other words, where it is now located)
City or country of origin
Dimensions of the work
Material or medium (oil on canvas, marble, found objects, etc.)
If you found the image in a book, you will also need the author, title, publisher information, date, page, and figure or plate number of the reproduction. If you found the image online, you will need an access date, the web site address (URL), and, in some cases, an image ID number.
Source: University of Cincinatti Libraries