Declare WooCommerce Support (With settings)

funtions.php

// Originally posted in official WooCommerce Github
// Re-posted by Robin Scott of Silicon Dales here https://silicondales.com/tutorials/woocommerce/declare-woocommerce-support-theme/ to aid understanding and benefit all in the Open Source community. Feel free to share are distribute as required!
function mytheme_add_woocommerce_support() {
	add_theme_support( 'woocommerce', array(
		'thumbnail_image_width' => 150,
		'single_image_width'    => 300,

        'product_grid'          => array(
            'default_rows'    => 3,
            'min_rows'        => 2,
            'max_rows'        => 8,
            'default_columns' => 4,
            'min_columns'     => 2,
            'max_columns'     => 5,
        ),
	) );
}
add_action( 'after_setup_theme', 'mytheme_add_woocommerce_support' );