I like Hugo, but I’ve not found a nice workflow to automatically put the images on a CDN.
I was thinking of making a GitHub action that uploaded the image from a given branch, deleted it, set the URL, and finally merged only the md files to main.
Why not put the whole site behind CDN?
If you're okay with the images being on a CDN, why wouldn't you also be okay with the HTML and CSS also being on the CDN? Just fronting the entire static site with a pull-through CDN is an easy solution that doesn't require any complicated workflow.