Hello fellow lemmings!

I’m a new lemming like many of you and I want to know a bit more about the inner workings of lemmy. So I just have a few questions

• If I’m part of instance A and there is a community C in instance B and I want to put a comment with a picture attached.
  • In which instance is the data (comment+picture) stored?
• Is it possible to migrate from instance A to instance B seamlessly while taking all my data?
  • If yes, will my username change from user@A to user@B?
  • If the username changes, how do my previous followers keep track?
• When I’m just viewing (not commenting) community C@B from instance A, is some amount of data (images/post text) is transferred from B to A?
  • If yes, is it kept for sometime or permanently?

These are just some questions that came to my mind. I’ll post more in the comments as they come.