Hello Jason M,
We regret to inform you that this is not possible at the moment. We think to change these dialogs, and will keep this functionality in mind.
If you need these functionality urgently, you could create a new dialog for the editor, and to use our APIs to take the images in the way you want. Here is a documentation on RadEditor custom dialogs
We are sorry that could not help you much at this time.
the Telerik team
Check out Telerik Trainer
, the state of the art learning tool for Telerik products.