"Even further, what plausible harm could come from a picture of a kid in a tub, for example?"

Knowing the kind of data mining that occurs with text, one would only expect that future mining would occur with images as well. So what happens when all public images of you from birth to present are indexed and used to make decisions about you? For example, what would happen if you tried to get health coverage and the company could look into these indexed images for all contact with known carcinogens to determine your ability or cost for health coverage?