I'm experimenting with a wiki at work, and I have a bunch of illustrations and various images that I wanted to automatically have available to me as I was editing. There are enough of them that adding by hand was onerous, and adding via FTP & manual manipulation of the database was equally unappealing. Here is a WWW::Mechanize script that will upload pngs to a wikipedia. Alter lines 5 through 9 to suit your installation of wikimedia

#! perl.exe
$|++;
use strict;
use WWW::Mechanize;
my $wikilogin = "http://example.com/wiki/index.php?title=Special:Userl
+ogin";
my $wikiuploader = "http://example.com/wiki/index.php?title=Special:Up
+load";
my $user = 'username';
my $pass = 'password';
my $description = 'Media uploaded via automation';
#
# begin real work here
#
my $agent = WWW::Mechanize->new();
$agent->get ($wikilogin);
my $form = $agent->form_name('userlogin');
$agent->field ('wpName',$user);
$agent->field ('wpPassword',$pass);
$agent->field ('wpRemember',1);
$agent->click ();

open (ERRFH, ">errored.txt");
while (<*.png>){
    $agent->get($wikiuploader);
    my $form = $agent->forms(1);
    if ($form) { #we've found the form, fill it out
        # fill out the body
        $agent->field('wpUploadFile', $_);       
        $agent->field('wpUploadDescription', $description);
        $agent->field('wpUploadAffirm',1);# and submit
        $agent->click('wpUpload');
        print "saved $_\n";
    } else {
        #something's gone wrong 
        #simple log for now
        #TODO: fill out w/ better logic.
        print ERRFH "$_\n";   
    }
}
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