Change the header image size for the Opti WordPress theme.

change-opti-header-image-size.php

<?php
/**
 * Plugin Name: Change Header Image Size
 * Plugin URI: https://prothemedesign.com
 * Description: Change the size of the header image in Opti.
 * Author: Ben Gillbanks
 * Version: 1.0
 * Author URI: https://prothemedesign.com
 */


/**
 * Change the header width.
 *
 * @param int $old_width Old width, we can ignore it.
 * @return int
 */
function opti_new_header_width( $old_width ) {
	return 1200;
}

add_filter( 'opti_header_width', 'opti_new_header_width' );


/**
 * Change the header height.
 *
 * @param int $old_height Old height, we can ignore it.
 * @return int
 */
function opti_new_header_height( $old_height ) {
	return 500;
}

add_filter( 'opti_header_height', 'opti_new_header_height' );