I actually find the whole exercise interesting. But instead of evaluating an image without revealing the artist post an image by an artist (well known or not so well known) and discuss why we like it or don't like it. I personally find discussing work in such a manner pretty interesting.
I think it was maybe about a year ago that bjorke posted some images from a gallery show which produced some good discussions (or maybe not so good?).
I think it was a show of prints by Gursky but I am probably way off base.