Everything in the picture is clear. lower quality for increasing size of picture is acceptable Because the new pixels must be created but how about reduce size of picture?
why? and does it possible to make image smaller without reduce quality and without redesign it?
Since there can be no half-pixels, when you reduce a 5x5 pixel grid by 50%, you must make a decision how to render 2.5 x 2.5 pixels.
In your example, the chimney width is not evenly divisible by 2, so you get a precision error. In the angled roof, I think one might refer to this as a quantization effect: a squaring off of a smooth function.
