How to custom premiumpress_image() sizes?

Hello, I have larger images on my listings showing on my homepage, how can I create my own crop size?

I currently use the this:
echo premiumpress_image($post->ID,””,array(‘alt’ => $post->post_title, ‘link’ => true, ‘link_class’ => ”, ‘width’ => ‘230’, ‘height’ => ‘160’, ‘style’ => ‘width’, ‘230px’ )); ?>

But it stretches / skews some images as the image crop size is 150×150, but I want to have a larger size, how can I do this with premiumpress_image() ?