You can't really do that with Vapor unless you can find a dependency that doesn't require any extra server updates. As far as I know, there is none at this point.
Another solution is using AWS services to manage this. Cloudfront can help you with this a lot. I'm not sure how well it integrates with Vapor, but you can always contact the support to see if they can help you out.
You can find more information here: https://aws.amazon.com/solutions/implementations/serverless-image-handler/