This would probably depend on how you have security setup for this directory, from my thinking you should not be able to see images from the secured directory on the non secured pages. You should be able to do a quick test of this though by uploading an image to the secure directory then create an <img tag on a non secured page and reference the image. Whatever result you see on this test page should match what you see on with the HTML editor pages if you have the images in the secure part of the site.