Use a reasonably-sized font: either 10 characters per inch or a 12 point font. And choose a font that is easy to read rather one that is decorative: "Arial," "Lucida," "Modern," "Palermo" or "Times New Roman" are some good choices. Scripted fonts are hard to read even if they do make your paper "look nice"; it is the content of the paper that is most important, and making it easy for your readers to understand that content is always a good choice.
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: