This class is used with the Theme Customization API to render the custom image control on the Theme Customizer in WordPress 3.4 or newer.
$wp_customize->add_control(
new WP_Customize_Image_Control(
$wp_customize,
'logo',
array(
'label' => __( 'Upload a logo', 'theme_name' ),
'section' => 'your_section_id',
'settings' => 'your_setting_id',
'context' => 'your_setting_context'
)
)
);