Publishing means that a file is copied to the destination directory and
possibly transformed in the process. The default transformation is to export
Org files as HTML files, and this is done by the function
org-html-publish-to-html, which calls the HTML exporter (see HTML export). But you also can publish your content as PDF files using
org-latex-publish-to-pdf or as
using the corresponding functions.
If you want to publish the Org file as an
.org file but with the
archived, commented and tag-excluded trees removed, use the
org-org-publish-to-org. This will produce file.org
and put it in the publishing directory. If you want a htmlized version of
this file, set the parameter
t, it will
produce file.org.html in the publishing directory1.
Other files like images only need to be copied to the publishing destination.
For this you can use
org-publish-attachment. For non-org files, you
always need to specify the publishing function:
|Function executing the publication of a file. This may also be a
list of functions, which will all be called in turn.
The function must accept three arguments: a property list containing at least
:publishing-directory property, the name of the file to be published
and the path to the publishing directory of the output file. It should take
the specified file, make the necessary transformation (if any) and place the
result into the destination folder.
 If the publishing directory is the same than the source directory, file.org will be exported as file.org.org, so probably don't want to do this.