Enabling MediaWiki upload

How to enable upload in MediaWiki? I had to

1. create and write-enable the upload directory (see $wgUploadPath and $wgUploadDirectory in mediawiki/LocalConfig.php),
   
2. enable upload ($wgEnableUploads = true;) and
   
3. disable mime type checking ($wgVerifyMimeType=false;) in LocalConfig.php. (Somehow I keep getting text/plain mime type for PNG images that are displayed correctly).