cURL multipart form data file upload

I searched long and hard with that as a search phrase, and only found others asking how to do it. I finally figure it out, Praise God!
If you are struggling with cURL trying to upload files as part of a POST action form in PHP, try this: cURL multipart form data file upload

I posted a brief explanation and my complete code (modified for privacy of course).

This link sat broken for quite some time, but has recently been restored!