Personally, I prefer to perform such optimizations on 'load' rather than on 'store' (as recommended by dgelks). This is particularly useful if you may want to

Personally, I prefer to perform such optimizations on 'load' rather than on 'store' (as recommended by dgelks). This is particularly useful if you may want to change your optimized image format. You would have a canonical lossless image stored in S3. When a user makes a request to your CDN, it calls an origin server (assuming a cache miss) that transforms the canonical images into an optimized form. Any basic WSGI, FCGI, CGI application behind NGINX will probably be sufficient.