Using Craft with CloudFront, and handling invalidation I'm trying to get static assets set up to be served by CloudFront. I know how to get the S3 bucket working, and have CloudFront serving from that bucket, but what I can't wrap my head around is how to handle the invalidation. In non-Craft instances I know about hashing to trigger the invalidation, but not sure how to do that in Craft. 

Specifically, if an editor uploads a photo named "photo.jpg", and then publishes, and decides to make a change and uploads the revised photo with the same name, how does CloudFront know that it has changed since the editors don't know about content hashing? 

Hopefully this makes sense. While not at all new to Craft, I'm very new to running it with performance in mind and even newer to using a CDN. Any help is greatly appreciated!
One way would be to manually clear it with Cloudfront Invalidation.