Theme customiser Header image uploads

As per foralien’s observation, is it possible for custom header images uploaded via the Theme Customiser to inherit width and height parameters?

$args = array(
	'flex-width'    => false,
	'width'         => 435,
	'flex-height'    => false,
	'height'        => 290,
	'default-image' => get_template_directory_uri() . '/images/header.jpg',
);
add_theme_support( 'custom-header', $args );

The above works fine if the image is uploaded via the standard theme header page, but height and width parameters are ignored by the header_image() call if the image is uploaded via the Theme Customizer.