Essentially, if you click the Insert/edit image button, then on the Source button to the right of the Source field in the popup, you can select the image from the assets library and then when you click Save it should appear in the editor.

There's an animation on this documentation page showing inserting an image. The editor has been updated since then with a nicer layout and new features, but the functionality is basically the same!

Thanks

Joe

OK, so can you give me some more information, because it seems to work fine for me when I go to your site and insert an image on a page from your assets library.

e.g., which page are you editing, and which image are you inserting?

Thanks

Joe