how can I show an image in editor?
In general you would want to create a extension which decorates ranges, see official decoration example.
An working example(octo.app): ink/images.ts at c4758965d91d9e2255d8062e4d7aef7f8b837a29 · writewithocto/ink · GitHub
could you share me an complately online demo, because version 6 is quite different with version 5, I am hardly to use it