Follow the below instruction and modify your code with my code
<!DOCTYPE html>
<html>
<head>
<title>Click, download file and redirect to another page</title>
</head>
<body>
<a href="23.jpg" download onclick="redirect()"><img src="fl.jpeg" class="img1" alt="Click, download file and redirect to another page" style="width:25%;"></a>
<script>
function redirect() {
setTimeout(function(){
window.location.href="imgcounter.php";
}, 3000);
return true;
}
</script>
</body>
</html>onclick=”return confirm(‘Are you sure ?’)”