how to build my own and upgraded image of nginx proxy manager?

[posta246]

Hi,
I'm asking to myself if there is a way - supposed answer: yes - and how, related to upgrading the software in the container.
I mean, if I want to upgrade nginx, certbot... and other tools/libs inside - for security reason - what could I do (hoping that the upgrades are minor changes and dont break the app code)?
I'm not a dockerfile expert and I have not understood if I can just rebuild the image with my own tag.
Someone might describe the workflow and the things that have to be modified, eventually (of course I should change the docker-compose)?
This could be useful for all of us that use npm and want to have an updated version before a new official image is published.
Thanks for anyone could give some tips!