Blurred, as if you squint: Marie Curie.
Two pictures in one
A face in the dots
Squint, or step back from the screen. Is there a picture?
Yes: Marie Curie.
Why? Each dot is a little bigger where the photo is dark, the way old newspapers printed photos. Close up, the dots hide it; squinting blurs them into the photo.
Picture: Henri Manuel, hidden in dots by Science Playground, Public domain · Wikipedia(opens in a new tab)