No, there's no setting for that. You will have to edit the source code if you want to achieve that.
This is what generates the thumb:
[CODE lang="php" title="app/lib/classes/class.image.php"]// Thumb sized image
$image_thumb = self::resize($image_upload['uploaded']['file'], dirname($image_upload['uploaded']['file']), $image_upload['uploaded']['name'] . '.th', $image_thumb_options);[/CODE]
You have to alter the $image_thumb_options
array and make sure to calculate the appropriate resolution for your thumbs which has to be reflected in the width
and height
array keys.