Here is an example of how to cite an artwork as seen in a museum. You may want to add the medium or format in square brackets after the title of the work for clarification.
van Gogh, V. (1887). Self-Portrait with a straw hat (obverse: the potato peeler) [painting]. The Metropolitan Museum of Art, New York, NY, United States.
Here is the citation for the same artwork from the museum website:
van Gogh, V. (1887). Self-Portrait with a straw hat (obverse: the potato peeler) [painting]. The Metropolitan Museum of Art, New York, NY, United States. https://www.metmuseum.org/art/collection/search/436532
If the photograph is associated with a museum, cite it the same way as the museum artwork examples above. Otherwise, add the medium "[Photograph]" after the title of the image for clarification. If the photograph has a specific date of production rather than just the year, include the full date.
Souza, P. (2016, October 26). President Obama, Vice President Biden and members of his national security team [Photograph]. NPR. https://www.npr.org/2016/10/26/499490029/photos-one-photographers-remarkable-chance-to-cover-the-president