Note that the "not-an-image.jpg" may not be uploaded to the live server because of persistent security warnings (correctly so)!
The following anchor links to a file that contains PHP code, but it has a
.jpg file extension. The
.htaccess file includes the necessary directive to process
.jpg files for PHP (although this may not be correct for the current live server).
not-an-image.jpg - a PHP file disguised as an image.
This is the same file, but with a
.php file extension: not-an-image.php