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:
When studying at higher levels of school and throughout college, you will likely be asked to prepare research papers. A research paper can be used for exploring and identifying scientific, technical and social issues. If it's your first time writing a research paper, it may seem daunting, but with good organization and focus of mind, you can make the process easier on yourself. Writing a research paper involves four main stages: choosing a topic, researching your topic, making an outline, and doing the actual writing. The paper won't write itself, but by planning and preparing well, the writing practically falls into place. Also, try to avoid plagiarism.