The 7th Edition of the Publication Manual of the American Psychological Association addresses artwork on p.346, section 10.4 Visual Works.
Artwork in a museum or on a museum website
The general format is: Artist, A.A.(date).Title of work [Description]).,Museum name, Museum location.url.if found on a website.
Seen in a museum:
​Wood, G. (1930). American gothic [Painting]. Art Institute of Chicago, Chicago IL, United States.
Seen on a museum website:
Wood, G. (1930). American gothic [Painting]. Art Institute of Chicago, Chicago IL, United States. https://www.artic.edu/artworks/6565/american-gothic
Parenthetical: (Wood, 1920)
Use this format for all types of museum artwork including paintings sculpture, photographs, prints, drawings, lithographs, installations. Use square brackets to enclose this description right after title.,