It's similar to generating compressed files with the build. I think it belongs on the web server layer. Here's an open source, self-hosted one, that should be

It's similar to generating compressed files with the build. I think it belongs on the web server layer. Here's an open source, self-hosted one, that should be easy to integrate with Next.js: https://github.com/willnorris/imageproxy https://github.com/willnorris/imageproxy To define a custom one, you need only provide a function: https://nextjs.org/docs/api-reference/next/image#loader https://nextjs.org/docs/api-reference/next/image#loader