How to change the default image size in the simpleviewer theme

I tried updating the simpleviewer/functions.php page as below

var $maxImageWidth="900";
var $maxImageHeight="500";

    var $preloaderColor="0xFFFFFF";
    var $textColor="0xFFFFFF";
    var $frameColor="0xFFFFFF";

    var $frameWidth="10";
    var $stagePadding="20";

    var $thumbnailColumns="3";
    var $thumbnailRows="10";

but i don't see my image any larger nor i am able to change the number of tumbnails colums/rows. Can someone please help.