return
		}

		rednessAt := func(x int, y int) uint32 {
			r, _, _, _ := m.At(x, y).RGBA()
			// Shift by 8 to convert from 16 bit color to 8 bit color.
			return r >> 8
		}

		// Round-tripping a still (non-animated) image.Image through
		// Encode+Decode should shift the origin to (0, 0).
		if got, want := rednessAt(0, 0), uint32(0x22); got != want {

Colours at the Lens before they enter'd the Composition of that beam. Thus, for instance, Cinnaber illuminated by this beam appears of the same red Colour as in Day-light; and if at the Lens you intercept the green-making and blue-making Rays, its redness will become more full and lively: But if you there intercept the red-making Rays, it will not any longer appear red, but become yellow or green, or of some other Colour, according to the sorts of Rays which you do not intercept. So Gold in this Light...

instance, Cinnaber illuminated by this beam appears of the same red
Colour as in Day-light; and if at the Lens you intercept the
green-making and blue-making Rays, its redness will become more full and
lively: But if you there intercept the red-making Rays, it will not any
longer appear red, but become yellow or green, or of some other Colour,