Using this code to add a custom header to function.php

add_theme_support( 'custom-header', $args );
$args = array(
	'width'         => 980,
	'height'        => 130,
	'default-image' => get_template_directory_uri() . '/imgs/header.jpg',
	'uploads'       => true,
);

not working. What am doing wrong please?
thx
D

First, you have to put the args array before you call the add_theme_support() function. This is because you have to define the args variable before you can use it, otherwise it is just an undeclared variable with a null value.

Second, you also have the various custom header functions in your theme’s header.php file. Those are what respond to the custom header args.

http://codex.wordpress.org/Custom_Headers