Thread:Extension talk:SmoothGallery/MW1.15 Not Working - Images on top of each other/reply (14)

Yes, one is different. ;) Watch out the  parameter. In the second case, it is $output = initSmoothGallery( $input, $argv, $parser ); instead of $output = initSmoothGallery( $input, $args, $parser ); which apparently won't work at all.