Thank you for your feedback. We are currently in public preview of static website hosting for Azure Storage to enable this scenario. Check out the blog post here for more details: https://azure.microsoft.com/en-us/blog/azure-storage-static-web-hosting-public-preview. The feature set includes support for default documents and custom error documents for HTTP status code 404.
For any further questions, or to discuss your specific scenario, send us an email at firstname.lastname@example.org.Toby commented
This is the exact problem I am facing, I would love to use azure cdn to cache dynamically created images (scaled or otherwise transformed version of an original). After the first request failing a custom 404 handler could create the image & add it for the next request.Toby supported this idea ·