<a id="gclid" href="lol"><img src="path/to/your/image.png" /></a>

<script>
var url = new URL(window.location.href);
var gclid = gclid.searchParams.get("gclid");
document.getElementById("gclid").href = "https://domain-a.com/index.html?gclid="+gclid;
</script>