Is it a historical photograph or a photograph published in a book that someone scanned and posted on line, is it a photograph of something like a sculpture? Is your paper focused on the work of the photographer, the makeup artist who prepared the model, the digital image enhancer who altered the image, the model? There is no single correct way to cite a photograph, because there are many different reasons to cite a photograph. Your instructor would be able to give you more specific advice. In general, though, the 8th edition of the MLA guide would say something like this:
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