Picture on resume is not mandatory. Users always can just to leave picture field blank and on resume it will shows default dummy/universal photo for all genders.
Why? Those are online resumes. Why they cannot be with pictures. These online resumes are for online presence. There is also print version of each resume.
All these resumes can be printed like a normal resumes on the paper with the same data. There is online version for online presence and print version for personal presence on the meeting with the employer.