如何根据选择的单选按钮切换两个以上的图像？

<input type="radio" name="image" id="image1" checked>
<label for="image1">图像1</label>
<input type="radio" name="image" id="image2">
<label for="image2">图像2</label>

<img src="image1.jpg" id="img">

var radioBtns = document.getElementsByName("image");
var img = document.getElementById("img");

for (var i = 0; i < radioBtns.length; i++) {
  radioBtns[i].addEventListener("change", function() {
    if (this.checked) {
      if (this.id === "image1") {
        img.src = "image1.jpg";
      } else if (this.id === "image2") {
        img.src = "image2.jpg";
      }
    }
  });
}