Yes. Good point. It's indeed quite expensive to do the graphic generation on the server.
We use a caching from Amazon CloudFront. They have a great feature 'custom origin'. We just put our heroku server URL as an origin for CloudFront and configured HTTP headers properly. After that we were able to significantly reduce the load on a server.
We use a caching from Amazon CloudFront. They have a great feature 'custom origin'. We just put our heroku server URL as an origin for CloudFront and configured HTTP headers properly. After that we were able to significantly reduce the load on a server.
We also blogged about it: http://blog.elastic.io/post/22773181715