The caption for a figure begins with a description of the figure, then the complete Works Cited list citation for the source the figure was found in. For example, if it was found on a website, cite the website. If it was in a magazine article, cite the magazine article.
Note the source is cited as any other reference in Works Cited
Short-Term Memory Test Involving Pictures. From Pike, Karen L. Short-Term Memory
Loss. Mackerlin Press, 2008, p. 73.