Yes. HTML editor will allow for local image upload and it works on Windows server.
In regard to any provision, that should be decided before using the HTML editor and allowing for image upload. However, the HTML editor works side by side with Security Assist and you can set who is able to use the image upload based on a rule that you specify in Security Assist (for example, you would only want users who logged in to be able to upload.).
The time it takes to upload an image depends on the server and the restrictions more than the HTML editor.