If the image, sculpture… etc is from a library database:

MLA:

Artists last name, first name. Italicized Title of Work. Date or the Acronym N.D is there isn’t a date. name of institution that houses the piece. City location of said institution.Name of Database. Web. Day you viewed the piece.

Lange, Dorothea. Migrant Mother. 1936. Library of Congress. Washington D.C. Farm Security Association Black and White Negatives. http://www.loc.gov/pictures/item/fsa1998021539/PP/. 5 February 2016.

APA:

Artist/Photographer. Year then month of publication. Title of piece. City, state of publication: Location of piece (Museum)/Publisher.

Dorothea Lange. 1936 February/March. Migrant Mother. Nipomo, California: Washington D.C Library of Congress.