If you are uploading to a location within your web root, you can simply add an image... I don't think you ever need an a href, so that part of the documentation may be wrong or you are misunderstanding it. Just add the image and specify the src as the field from your database (and add in the upload directory before it).
If you are creating secure images you need to create a page that will download the image using the download file server behavior that comes with Digital File Pro. Then specify the src of the image as that download page and pass a parameter to allow you to filter the recordset on that page so that the correct image is displayed, but that doesn't seem to be what you are doing.