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 {