Implement generating of an image and inserting it into the clipboard on copy/cut so it can be pasted in MS Paint or other tools for image editing.

Attaching to the CommandExecuting event of RadRichTextBox and handling the copy command can be used as a workaround:
CopyCommand command = e.Command as CopyCommand;
  
if (command != null)
{
    ImageInline image = this.radRichTextBox.Document.Selection.GetSelectedSingleInline() as ImageInline;
    if (image != null)
    {
        Clipboard.SetImage(image.ImageSource);
        e.Cancel = true;
    }
}