We tried to build a simple document management system on top of our Knack app, but the Knack does not allow image to be embedded in the Rich Text field. Instead, it requires the image to be an URL link, which many users do not know know how to upload image.
Can I suggest to allow an image point to a Knack image database, and user can simply cut-and-paste in the Rich Text field. This can also prevent the image to be exposed to public, as it's part of the database.
I think the development is going to be tough, but it will be a very handy function.