Ok, had to switch over to my laptop, can't debug stuff from my phone lol.

This should work for you.

Code:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<!-- saved from url=(0039)http://www.suresure.co.uk/Temp/BM3.html -->
<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        
        <title></title>
        <style type="text/css">
            img:hover{
cursor: pointer;
            }
        </style>
<script type="text/javascript">
function toggle(el) {
	if (el.class === undefined) {
		el.class = "";
	}
	if (el.class !== undefined && el.class.match(/enlarged/) === null) {
		el.class += " enlarged";
		el.width = el.width * 2;
		el.height = el.height * 2;
	} else {
		el.class = el.class.replace(/\senlarged/,"");
		el.width = el.width / 2;
		el.height = el.height / 2;
	}
	return true;
}
</script>
    <style type="text/css"></style></head>
    <body>
            <img src="./BM3_files/biscuitman.svg" onclick="toggle(this)">
            <img src="./BM3_files/biscuitman.svg" onclick="toggle(this)">
    
</body><link rel="stylesheet" type="text/css" href="data:text/css,"></html>