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:
The eighth edition of the MLA Handbook , while suitable for writers at all levels, is designed with teaching students in mind. It explains the principles behind citing sources, provides instruction on the MLA’s system of documenting sources, and offers detailed guidelines on the mechanics of scholarly prose. The handbook includes guidelines on plagiarism and academic dishonesty, tips on evaluating sources, and a worksheet for creating works-cited-list entries. The eighth edition’s system of documentation supersedes the guidelines set out in the seventh edition and in the MLA Style Manual .