Wordpress Milan Theme - how to add image grayscale to the frontpage

In the Milan Theme I'd like my images a little larger.  On investigation they resize the image to width 192 and height 160

To make this change

OPEN wp-content/themes/milan/index.php

FIND

$width="192";       
$height="160";

I REPLACED this for

        $width="187";       
        $height="319";