CDN for fast picture upload

Hallo support,
I have used WPmudev CDN facility for fast picture upload for years. I know you have changed a lot, but I’m confused about problems with loading my picture on my site The speed of the site is so slow.
I use Hummingbird Pro and Smush Pro, but I think Hummingbird Pro aren’t configure correct.
I use WP Engine as host and are not interesting in changing. How do I establish my CDN for picture again?
I have a lot of project just now and haven’t time to read all the documentation. I hope you can shortcut my learning curve and give me a hint what to do.
On beforehand thank you
Bo Folkmann