You pay someone in a developing nation $1.00 per day to look at thousands of photos of shit. Like, how do people think Facebook moderation and semantic labeling happen? Cheap labor in places with no labor laws. It was ever thus.
I meant that they train their system on pictures where they have the underlying medical data. Their system might still be total crap (teehee), but I'm guessing that they at least try to make it predictive/generalized.