The answer to this question is yes you can....but there is a Mb limit....if the file is under 2MB you can upload it to a post, if the file is under that limit....Just use the "File Manager" in Post Options...Browse to the file; select it, and click "Add File"...wait till it loads....and then click "Done adding files" .....it will not preview, just click "Submit" and when the submitted post appears, there it will be.
