PeterKatoff

Do you have a proxied website on cloudflare with an orange-clouded DNS Record? This is required to serve images directly from Cloudflare DNS. A free account will make you eligible, but you might want to check out a pro account which offers a lot more and is not that expensive.

If you do not want a Cloudflare account choose the Variants Tab in Cloudflare Images, Then Click on the copy icon to copy the url. Replace your current url with the Cloudflare url in The WordPress Block Editor.

Thank you Anton.

Solved my own problem. There is a plugin for this (of course). Installed Enable Media Replace Plugin. Allows replacing Media Library image file with New image file without changing the file name. Replaced existing image file in Media library with the exact same image file located on my computer. Effectively updates the image file in Media Library, and then it automatically offloads to Cloudflare. Some work involved but not so bad. Just have to update the existing images in Media Library and then purge cache.