[RESOLVED] Trouble uploading after installation
For me chmoding uploads, uploads/*, uploads/*/* uploads/*/*/* to 777 helped (but please check with someone mor wiki-security aware that this doesn't imply any threats). For you it may be images, images/*, ... as it seems our wiki has some special settings.
Making things 777 means any user can write to the directory, which means if anyone somehow gets access to your server (aka security vulnrability in something else), or if there are other users of your server, they can write stuff to the images directory. A better approach is to make the images folder either owned by the apache user, or in the apache's user's group, and only let the apache user have said permissions.