I saw two examples. The dog/girl one has obvious artifacts in the picture of the girl. The directly linked image doesn't have artifacts, but putting them side by side, I can see what got matched up and they're still very approximately the same picture in that they're both pictures of women and the eyes are in the same part of the picture which gives support to your perspective. I do still wonder whether it would be possible to take, say, a (legal) nude and turn it into an innocent-looking image that still matches the hashes or not. I'm more inclined to believe it now than before, but theoretical possibilities don't usually map to realistic concerns.¹

1. One example of this would be that theoretically, LaTeX's cross-reference mechanism can get caught in a cyclic state. This can only happen with page references and the most likely scenario is a reference to a roman-numeraled page number where if the page reference is output as ix the referenced location moves to page x and when the page reference is updated to x the referenced location moves to page ix (in practice, functioning examples required a shift between xcix and c, but either way, the probability of this happening in a real document is vanishingly small).