Notice this image is numbered - "Figure 1". Then comes the image caption - what you want your reader to know about the image. Lastly is the credit line in brackets. The website that this image comes from (Te Papa Tongarewa Collections Online) requires the given credit line to be placed with the image.
Figure 1: Founded in 1894, the oldest music school in New Zealand. (Academy of Music, Nelson, 1904, Dunedin, by Muir & Moodie studio, maker unknown. Te Papa (O.036729)).
Credit line in this example is similar to a footnote reference, and here I have included the original source of the map. I could alternatively put this in my List of Illustrations at the end of my work.
Figure 2: The site of a weekend house built out of the rock. Map of building site, March 1935. Topographic Map oringinally courtesy Avery Library, Columbia University, here from Donald Hoffman Frank Lloyd Wright's Fallingwater: The House and it's History, 3rd ed. (New York, NY: Dover Publications,1993),14.