The full photo it was cropped from has her posing mostly nude: http://www.lenna.org/full/len_full.html http://www.lenna.org/full/len_full.html While the test

The full photo it was cropped from has her posing mostly nude: http://www.lenna.org/full/len_full.html http://www.lenna.org/full/len_full.html While the test image itself doesn't show much, the fact that it originated from Playboy magazine is widely known – and presumably has contributed to the image's popularity. It's a sort of in-joke: you can't understand it just by seeing it, you need the context. But it's an in-joke that recalls sexist tropes.