On the other hand, A Pixel Is Not A Little Square[0] would disagree, a raster is a grid sample of a continuous function.
Pictures of cats, subpixel rendered text, or company logo SVGs as displayed on a web page are point samples and not little squares.
User interfaces are good examples of often being little squares. Calling HN's beige background a point sampled discrete representation of an underlying continuous function seems pretty tortured — to me it seems like a bunch of beige little squares.