How to properly implement different image sizes?

Question

Django

The user on the site has an avatar. There are places on the site where you want to display the user's avatar of a small size (20x20). So, how to organize all this business? When a user uploads a new avatar, create copies with the required sizes, or compress on the fly for each request (Ha-Ha)? Or give the original everywhere, and then the browser compresses the path through css to the desired size?
I am working on nginx-django. Maybe they already have ready-made solutions for such things?

Answer 1

Maybe sorl will work for you.