<img
      id="image"
      src="https://previews.123rf.com/images/vanatchanan/vanatchanan1502/vanatchanan150200214/36790697-on-%EB%B0%8F-off-%EC%9C%84%EC%B9%98-%EC%8A%A4%EC%9C%84%EC%B9%98-%EB%B2%A1%ED%84%B0-%EC%9D%BC%EB%9F%AC%EC%8A%A4%ED%8A%B8-%EB%A0%88%EC%9D%B4-%EC%85%98-.jpg";
      height="200px"
      width="200px"
    />
    <script>
      var off =
        "https://previews.123rf.com/images/vanatchanan/vanatchanan1502/vanatchanan150200214/36790697-on-%EB%B0%8F-off-%EC%9C%84%EC%B9%98-%EC%8A%A4%EC%9C%84%EC%B9%98-%EB%B2%A1%ED%84%B0-%EC%9D%BC%EB%9F%AC%EC%8A%A4%ED%8A%B8-%EB%A0%88%EC%9D%B4-%EC%85%98-.jpg";;
      var on =
        "https://previews.123rf.com/images/vanatchanan/vanatchanan1502/vanatchanan150200213/36790484-on-%EB%B0%8F-off-%EC%9C%84%EC%B9%98-%EC%8A%A4%EC%9C%84%EC%B9%98-%EB%B2%A1%ED%84%B0-%EC%9D%BC%EB%9F%AC%EC%8A%A4%ED%8A%B8-%EB%A0%88%EC%9D%B4-%EC%85%98-.jpg";;
      var image = document.getElementById("image");

      image.onclick = function () {
        if (image.src == off) {
          image.src = on;
        } else {
          image.src = off;
        }
      };
    </script>

전 이렇게 했었네용