NOT AN ANSWER, just suggestions/ideas that include code. A structured/formatted comment.
Unsure how to use/code them in C++, but this is just an issue of rendering HTML and implementing javascript code.
The essentials are:
Have jQuery lib loaded. One way is:
<head>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
</head>
Use a javascript code block for your jQuery script:
<script type="text/javascript">
$(document).ready(function() {
$('#mybutton').click(function() {
var pic = $('image_selector').val();
$.ajax({
type: "POST",
url: "ind.php",
data: "img=" + pic
})
.done(function(recd) {
$('#txtHint').html(recd);
});
}); //END mybutton click
}); //END document.ready
</script>
I don't know how you would send a pic as a var, or how to structure that, but you get the basic gist...
On the server side, it works like this (using PHP for eg):
<?php
$image = $_POST['img'];
//Do something with the received image
Actually, now that I'm thinking about it, you are sending an image (something I haven't done before), so I don't think you can just send it like text or a JSON object... You may need to post it with the enctype='multipart/form-data
attribute for file uploads, as you do when using a form for uploads? Just guessing.
Anyway, this is not intended to answer your question, just to give you some hints as to where to look further.
See these simplistic examples for the basics of AJAX: