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:
Format for entries: A single space is used after any punctuation mark. When dividing a long word or URL onto two lines, put hyphen, slash, or period at the end of the line. Do not add a hyphen to a URL that was not originally there. Never begin a new line with a punctuation mark. Double-space all lines in a bibliography entry. Do not indent the first line of a bibliography entry, indent second and subsequent lines 5 spaces, or 1/2″ ( cm) from the left margin. Please see Chapter 11. Guidelines on How to Write a Bibliography for details.
When you are writing your report, you will use the sources in your bibliography to remind you of different facts and background information you used for your science fair project. Each time you use some information from a source, you will need to cite the source that it came from. To cite a source, simply put the author's name and the date of the publication in parentheses (Author, date) in your text. If the person reading your report wants to find the information and read more about it, they can look up the reference in your bibliography for more detail about the source. That is why each source you use must be listed in a detailed bibliography with enough information for someone to go and find it by themselves.