How do you cache AI-generated images on a multi-CDN setup?

I'm running an AI image generator project called ImagesArt (https://imagesart.ai) where users turn text prompts into images. We're serving hundreds of thousands of generated images per day and each one has a unique URL, so traditional CDN caching strategies don't fully apply.

For folks using Mlytics or similar multi-CDN setups: how do you handle cache TTL for unique-URL media assets? Cost gets painful when 80% of generated images are viewed only once. Any tips on cache key normalization, edge purging on regenerate, or smart-routing rules would be appreciated.

Thanks!