$EnableUpload The upload.php script is automatically included from stdconfig.php if the $EnableUpload variable is true in config.php. Note that one may still need to set an upload password before users can upload (see UploadsAdmin).
$UploadDir The directory where uploads are to be stored. Defaults to uploads/ in the pmwiki directory, but can be set to any location on the server. This directory must be writable by the webserver process if uploading is to occur. $UploadUrlFmt
The url of the directory given by $UploadDir. $IMapLinkFmt['Attach:']

The format of the upload link displayed when an attachment is present. No default is set.
$LinkUploadCreateFmt The format of the upload link displayed when an attachment not present. Defaults to  <a class='createlinktext' href='\$LinkUpload'>\$LinkText</a> <a class='createlink' href='\$LinkUpload'> Δ</a>");

$UploadPrefixFmt Sets the prefix for uploaded files to allow attachments to be organized other than by groups. Defaults to '/$Group' (uploads are organized per-group), but can be set to other values for sitewide or per-page attachments.
    $UploadPrefixFmt = '/$FullName';    # per-page attachments
$UploadPrefixFmt = ''; # sitewide attachments  $EnableDirectDownload
When set to 1 (the default), links to attachments bypass Pm Wiki and come directly from the webserver. Setting $EnableDirectDownload=0; causes requests for attachments to be obtained via ?action=download. This allows Pm Wiki to protect attachments using a page's read permissions, but also increases the load on the server. $EnableUploadVersions
When set to 1 (default is 0), uploading a file to a location where a file of the same name already exists causes the old version to be renamed to file.ext,timestamp (instead of being overwritten). timestamp is a Unix-style timestamp.
$UploadNameChars The set of characters allowed in upload names. Defaults to "-\w. ", which means alphanumerics, hyphens, underscores, dots, and spaces can be used in upload names, and everything else will be stripped.  $UploadNameChars = "-\w. !=+";    # allow exclamations, equals, and plus

\$UploadMaxSize