Header Image: how to change height 198px to smaller

Problem is: after uploading a header image, the height is always 198, this is NOT what we want.

How to change it?
You can not change in style.css, but here:

function.php

// We’ll be using post thumbnails for custom header images on posts and pages.
// We want them to be 940 pixels wide by 198 pixels tall.
// Larger images will be auto-cropped to fit, smaller ones will be ignored. See header.php.
set_post_thumbnail_size( $custom_header_support[‘width’], $custom_header_support[‘height’], true );

$custom_header_support = array(
// The default image to use.
// The %s is a placeholder for the theme template directory URI.
‘default-image’ => ‘%s/images/headers/path.jpg’,
// The height and width of our custom header.
‘width’ => apply_filters( ‘twentyten_header_image_width’, 940 ),
‘height’ => apply_filters( ‘twentyten_header_image_height’, 198 ),
// Support flexible heights.
‘flex-height’ => true,
// Don’t support text inside the header image.
‘header-text’ => false,
// Callback for styling the header preview in the admin.
‘admin-head-callback’ => ‘twentyten_admin_header_style’,
);

My real image is this: height is 145