chimerically

I would have to agree. It may be that your professor is simply not tech-savvy and has no idea of the proliferation of interaction and self-definition using personal photography online these days. Nevertheless, I would take it as an opportunity to explore your idea, especially the reasons you may expand it into a thesis next semester, and appreciate that you have to defend it. If you can make your case and argument with someone who is "enh" about your idea, then you should definitely be able to do the same with people who are more sympathetic and open to it. I understand how it would injure your self-esteem, but try to not let it do that and instead learn and grown from it. You know that you have a valid idea and possible thesis, convince your professor of the same.