Modify product gallery thumb aspect ratio

ci-woo-gallery-thumb.php

<?php

// Added on 'after_theme_setup'.
add_filter( 'woocommerce_get_image_size_gallery_thumbnail', 'ci_theme_woocommerce_gallery_thumb_size' );
function ci_theme_woocommerce_gallery_thumb_size() {
	return array(
		'width'  => 150,
		'height' => 203,
		'crop'   => 1,
	);
}