The College Art Association's Art Bulletin style is a modification of the Chicago Manual of Style. It gives the most thorough information, and is widely seen as the preferred style to use. Scroll down to their Captions sections:
Captions should be numbered consecutively. Figure numbers do not include a period. A full caption includes, whenever available and appropriate, information in the following order:
Figure number with no period
Artist (first name, last name)
Title (in italics)
Medium on support
Dimensions in inches (h. x w. x d.) followed by dimensions in centimeters (1 inch = 2.54 cm)
Name of collection
City of collection
Other collection information such as "gift of . . . ," accession number, etc.
Copyright or credit line information regarding both the photograph and the artwork (in parentheses)
1 Sandro Botticelli, Primavera, ca. 1482, tempera on panel, 6 ft. 8 in. x 10 ft. 4 in. (2.03 x 3.15 m). Galleria degli Uffizi, Florence (artwork in the public domain; photograph provided by Scala/Art Resource, NY)
2 Steichen, Edward. Enlisted Men of the USS Lexington. 1943. Art, Architecture & Engineering Library Collection. University of Michigan. March 21, 2009.
3 William Kentridge. Multimedia Interactive Feature. San Francisco: San Francisco Museum of Modern Art, 2009. Explore Modern Art. March 2009. San Francisco Museum of Modern Art. March 21, 2009.