How to override customizer.php controls in Parallax One

This document will show you how to override controls in customizer.php in Parallax One.

First of all, you need to create a child theme. After creating the child theme, make a file named functions.php in which you should add this function:

function parallax_one_childtheme_customize_register( $wp_customize ) {
$wp_customize->add_setting( 'parallax_image_child' );
$wp_customize->add_control(
    new WP_Customize_Image_Control( $wp_customize,'parallax_image_child',
        array(
            'label' => __('New parallax control from child theme','parallax-one'),
            'section' => 'parallax_one_ribbon_section',
            'priority'   => 15
        )
    )

);
add_action( 'customize_register', 'parallax_one_childtheme_customize_register' );

The above code will add in the Ctuomizer, in the ribbon section an image control.

Next step is to create a sections folder into your child theme and copy the file parallax_one_ribbon_section.php from your parent theme and add the following code:

$parallax_one_new_image = get_theme_mod('parallax_image_child'); 
echo '<img src="'.$parallax_one_new_image.'"/>';<br>

Add the following code right where you want to add the image. 

For further details about how to add or remove customizer controls, please have a look at:  https://developer.wordpress.org/themes/advanced-topics/customizer-api/ and http://wordpress.stackexchange.com/questions/58932/how-do-i-remove-a-pre-exising-customizer-setting.