Lemmy is a federated platform. That’s a new (or at least newly popular) term, but it’s not a new concept. It’s a lot like email, and the answers are going to be the same, for the same reasons:

Can you be banned from lemmy email ?

Not really. Your specific email provider might ban you, in which case you’d need to get a new email address from a different provider. Same deal with Lemmy; your Lemmy instance’s admins might ban you, but they have no power over other instances.

Where can i find the rules?

Your provider will have their own rules. Most email providers will have rules about not spamming, or conducting illegal activity, etc. etc. Most Lemmy instances will have some basic rules that boil down to “don’t be a jerk” listed in the sidebar on the main page. I see that your instance does exactly that.

why do need picture every time i post

I’m not sure what you mean. Can you elaborate?