1) Am I right to say there are 2 copies of each images (and their thumbnails) on my server and S3?
2) What does it mean by the following?
Prepare the CDN by: . Check if some objects appear to be missing. objects from the CDN if needed. if the domain name of your site has ever changed.
Is it optional?
3) Will anything go wrong if I delete images on my server to clear up spaces? (I should not touch the images in on S3 of course, if I ever mess them up, I can be responsible for that :D)