How to add images to package documentation page?

I want to create a Howto for my package. I added a documentation page. But the text editor doesn't allow adding images from upload or clipboard. It only has a link insert thing which is not working either (image uploaded into a cloud doesn't load).

How can I add my images to the page?

Why not use a standard concrete5 editor? The one there is an abortion and is not suitable for making documentation, it's only good for plain text stuff.