Loading jquery causes web pixel to be requested twice

Loading jquery causes web pixel to be requested twice

MacOS 10.12.5
Jquery versions: 1.12.4, 2.2.4, and 3.2.1
Browsers: Chrome 58, Firefox 53.0.3, and Safari 10.1.1

If I load jquery before the image, there are two requests for the web pixel when the page is loaded.
  1. <!DOCTYPE html>

    <html>

    <head><title>Before</title></head>

    <body>

    <script src="http://code.jquery.com/jquery-1.12.4.min.js" type="text/javascript"></script>

    <img src="http://example.com/pixel.php">

    </body>

    </html>

However, if I load jquery after the image, there's only 1 request for the web pixel when the page is loaded.
  1. <!DOCTYPE html>

    <html>

    <head><title>After</title></head>

    <body>

    <img src="http://example.com/pixel.php">

    <script src="http://code.jquery.com/jquery-1.12.4.min.js" type="text/javascript"></script>

    </body>

    </html>