Photos can strongly suggest things like race and gender, but those and other prohibited axes for discrimination by most employers can also be strongly suggested b names, names of schools, names of particular awards/achievements, and names of past employers and jobs (particularly, e.g., when those employers are the kind that are permitted certain forms of discrimination that is generally prohibited.) Further, photos don't provide indication of anything that the prospective employer wouldn't get from an in person interview, which is a common step in the hiring process.