If you look at wkhtmltox, there’s native lib/app for converting a webpage to an image.
<?php // file: img.php
$img=render_image($_GET['url']);
?>
<!-- Your Website -->
<img alt="ldr"/>
<script type="text/javascript">
$(document).ready(function(){
var url="http://google.com/";
$('#img').attr('src','img.php?url="+encodeURIComponent(url));
});
</script>
In case the comment wasn”t clear enough, you need PHP somewhere which could run a native program.