func TestPaletted(t *testing.T) {
	f, err := os.Open("../testdata/video-001.png")
	if err != nil {
		t.Fatalf("open: %v", err)
	}
	defer f.Close()
	video001, err := png.Decode(f)
	if err != nil {
		t.Fatalf("decode: %v", err)
	}
	b := video001.Bounds()

	cgaPalette := color.Palette{
		color.RGBA{0x00, 0x00, 0x00, 0xff},
		color.RGBA{0x55, 0xff, 0xff, 0xff},
		color.RGBA{0xff, 0x55, 0xff, 0xff},