Format: 

Lastname, Firstname. Title of Work. Date of Composition, Repository or Collection, City. Medium. Database Name or Title of Website, Publisher, Day Month Year, URL. Accessed Day Month Year.

Lastname, Firstname. Title of Work.Date of Composition, Repository or Collection, City. Medium. Title of Book, edited by Firstname Lastname, Publisher, Year, Page(s).

Examples: 

Turner, Joseph Mallord William. Norham Castle, Sunrise. 1845. Oil on canvas. Tate Gallery. Tate: Art and Artists. tate.org.uk/art/artworks/turner-norham-castle-sunrise-n01981.. 14 Aug. 2015.

In-text: (Turner)

Photograph of Sagrada Familia. N.d. Photograph. Trip&Rate. Web. 14 Aug. 2015.

In-text: (Photograph of Sagrada Familia)

Eder, Josef Maria, and Eduard Valenta. Zwei Goldfische und ein Seefisch (Christiceps argentatus). 1896. Photogravure. The Metropolitan Museum of Art, New York.

In-text: (Eder and Valenta)

Manet, Edouard. La Rue Mosnier aux Drapeaux. 1878. Oil on canvas. J. Paul Getty Museum, Los Angeles. World Art: The Essential Illustrated History. Ed. Karen Fitzpatrick. London: Flame Tree, 2006. 215. Print.

In-text: (Manet)

Notes: 

If a title is not available, provide a brief description (not italicized) (MLA 29). If you are viewing the actual object in a museum or collection, provide the museum name and city after the date (see third example) (MLA 49); otherwise, for reproductions of images include the standard publication information following the full image citation. For the in-text citation, if you are citing multiple works by the same artist, include a short form of the work's title after the artist's last name. If relevant to the discussion, you can include the medium of the work (e.g. Oil on canvas) after the date of composition or city of the repository (https://style.mla.org/citing-images-viewed-firsthand-or-online).

Source:
MLA - p. 49