These are guidelines. Always check with your professors for their preferences.

From a Database (e.g. AP Images, ARTStor):

Image databases typically have metadata, such as the name of the photographer and the location the photograph was taken, associated with each image. Likewise, some image databases may include a description of the photograph which can be used for the image caption.

Structure:

Last, First M. Photograph Title. Month Date, Year Created. Collection, Museum/Institution,

       Location. Accessed Month Date, Year. URL of database.

Example:

The following image is from the AP Images database:

A black and white photograph of Fidel Castro giving a speech to a large crowd in 1959.
Fig. 1 Fidel Castro gestures as he addresses a crowd of several hundred thousand persons gathered in the park in front of the presidential palace in Havana, Cuba, in Jan. 1959.

To cite this image, use the metadata information provided by AP Images. For this particular image, the metadata includes the following:

A screenshot of metadata associated with an image found in an online image database.

Using the metadata available from AP Images to cite this particular image, the citation would be the following:

Valentine, Harold. Fidel Castro gestures as he addresses a crowd of several hundred thousand

        persons. January 1, 1959. Associated Press. Accessed 3 May 2017.

        http://classic.apimages.com/OneUp.aspx?st=det&kw=cuban%20revolution%20fidel%201959&ids=FIDEL%20CASTRO%201959%20REVOLUTION&showact=details&sort=relevance&intv=None&sh=14&kwstyle=and&adte=1488552435&pagez=40&cfasstyle=AND&rids=8b81173164e5da11af9f0014c2589dfb&dbm=PY2000&page=1&xslt=1&mediatype=Photo

The AP Images database also includes a description for this particular image, which can be used for the image caption.

A screenshot of an image caption for an image found in an online database.

From a Website:

Depending on the website, metadata about the image might be available.

Structure:

Last, First M. Photograph Title. Month Date, Year Created. Collection, Museum/Institution,

      Location. Accessed Month Date, Year. URL of website.

Example:

The following image is from Wikipedia:

A poster on the side of a building with the faces of three key people from the Cuban Revolution.
Fig. 1 Three Heroes of the Cuban Revolution.

To cite this image, use the metadata information provided on Wikipedia. To access the image's metadata on Wikipedia, double click on the image. For this particular image, the metadata includes the following:

A screenshot of metadata associated with an image found on Wikipedia.

Using the metadata available from Wikipedia to cite this particular image, the citation would be the following:

Tumpatumcla. Outdoors in Havana, Cuba, Showing Three Heroes of the Cuban Revolution.

        4 November 2012. Accessed March 3, 2017.

        https://commons.wikimedia.org/wiki/File:Outdoor_em_Havana,_Cuba.jpg

From Print (e.g. book, journal article):

Depending on the book or journal article, some metadata about the image might be available.

Structure:

Last, First M. Photograph Title. Month Date, Year Created. Collection, Museum/Institution,

      Location. In Book Title. Author First Author Last. City: Publisher, Year Published. Page/Plate

      Number.

Example:

A black and white photograph of Che Guevara surrounded by several men who are dressed in military uniforms.
Fig. 1 Homage to Ernesto “Che” Guevara’s Final Struggle.

Alborta, Freddy (photographer). Homage to Ernesto “Che” Guevara’s Final Struggle. In Cuban

     Palimpsests. Minneapolis: University of Minnesota Press, 2005.

Original Photograph:

If you were the photographer for the image, you would cite yourself.

Structure:

Last, First M. Photograph Title. Month Date, Year Created. Collection, Museum/Institution,

      Location.