AJAX request not routing through proxy

If your AJAX is a ‘post’, or for that matter any protocol, to URL2PNG the client is doing so directly. The client isn’t aware of, nor would it honor you server’s proxy configuration.

Considering the brief read of URL2PNG docs, placing your API key and password in your JavaScript/jQuery is risky at best since you’d be exposing that information to any site visitor willing to view the source of your page/document.

Perhaps you need to write a handler within WordPress and make your AJAX call directly to your site.