Hi Soliht, sorry for the late.
You’re right, it is not possible to upload images at the moment for the user I mean, not from the editor.
That because WordPress make it available only for admin users, that’s why you can do it in back-end.
Next version will come with a dedicated tool for that, for the moment just suggest to the users to upload the image somewhere, like on cloud or on them site, and use the url in the Text tab of the editor, with the img tool.
Thanks again for you accurate feedback, I can’t wait to start developing all this stuff.