The address to an applet would be
http://yoursite.com/folder/pagename.html or http://yoursite.com/pagename.html if not in a folder.
The .jpg has to be a part of the .html/webpage same as the java applet.
Remember you need to up load all the files produced for you by PTViewer Scripter or Panoweaver.
(OK I see you are asking about a "parameter" I didn't pick up on this before)
Sorry, I don't have the answer!
Hope this helps, Smooth