Ask HN: What the best way to optimize images in S3?

For this sort of work I found using a lambda function with a trigger on s3 upload works very well, aws-lambda-image seems like a popular project to use instead of writing your own code https://github.com/ysugimoto/aws-lambda-image

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.

I have a microservice setup to process my s3 images, on the fly and when they're uploaded.