Aβ plaques in the brain: Either you have them, or you don’t. At least that is what widely used, up-down PET tracer thresholds would have you believe. Not so. Researchers have developed a staging model of Aβ deposition based on the regional progression of Aβ pathology through the brain. Constructed and validated with data from more than 600 volunteers, the four-stage scheme correlated with clinical disease stage, and detected Aβ in many cognitively normal people who would have been considered Aβ-negative by binary, global measures alone.
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: