Override ZenPress header image dimensions

functions.php

    function zenpress_setup()
    {

        // This theme supports a custom header
        // Change the width and height here
        $cooking_header_args = array(
            'width'       => 1250,
            'height'      => 400,
            'header-text' => true,
        );
  
        add_theme_support('custom-header', $cooking_header_args);

  }
/**
 * Tell WordPress to run zenpress_setup() when the 'after_setup_theme' hook is run.
 */
add_action('after_setup_theme', 'zenpress_setup');