Just an idea, but if 100% honest opinions on apparence and who pass or not is the goal, then wouldn't it be better to show the uploaded pics for a bunch of strangers instead, and then write down the voting-results by each and everyone to each photo?
Or perhaps even better; the pics could potentially also be printed out in Photocopies that could be shown to random strangers on the street, which would be a much better option for honest opinions, as the current guy giving the opinions on each photo already knows that each and everyone is MTF, and not the least, he is only one person whos opinions may be very biased.
The only way to do a thing like this would be in a true survey-style, really.