I’m not sure how to approach this. My first idea is to use 's Victory Plugin or C++ to get access to the file system, then open a web page using Unreal’s web viewer, and have the web page take care of everything else (which means you have to know a little bit about web development to get it working).
But you can do it without a web page too, you just need to send the image using each of those services’ APIs, but again that involves knowing a little bit about web development.
Anyone else know how this works?