Yeah, your concern is totally valid. One thing that would hit people who cache the API is they would also be subject to fair use policies for bandwidth usage (namely serving the images used). Pretty much all CMSs have some form of this that basically requires large bandwidth users to pay for one of the higher price plans anyway so not to be losing money on customers

That said if someone wanted to get real fancy they could comb through the content and replace the image URLs with some of their own. You are right, this will have to be sorted out if this becomes a common way people use the product.

Thank you for the feedback

No problems. What made me think of it wasn't so much trying to avoid paying for the service, but because I'd want to run a cache for speed of the initial page load. If you are serving your images from a CDN that would be compatible with my goal to keep the site fast.

I don't think anyone would "could comb through the content and replace the image URLs" to save a few dollars, as the development effort would far outweigh the cost savings. So maybe you are OK there.