I never used a CDN before so this is a noob question, but how does it work on the tech side.
For example right now when a user uploads an image on my site it is uploaded to the "/uploads" folder at the root of my "www" folder via PHP. If I use Amazon S3, how will I make the images my users upload, go directly to Amazon's servers instead of mine?
Or does it work a different way like the images are still uploaded to my server but then I have to move them to the amazon server either manually or through a CRON job? Basically can someone explain to me how it works?