You can follow this guide to use the static content in Google cloud bucket to be distributed via cloud cdn. The origin would be the cloud bucket where you already have your static image content. CDN is not just for an SEO point of view but would deliver static content from Edge locations which are more closer to the end users. And also would reduce cost of directly accessing your storage bucket directly by caching the static content in CDN and serving it to end users from the cache. https://cloud.google.com/cdn/docs/quickstart-backend-bucket-console