From the WordPress support group… Just paste this code into your functions.php file, once you’ve created a child theme.
<?php
define( 'HEADER_IMAGE_WIDTH', apply_filters( 'twentyeleven_header_image_width', 970 ) );
define( 'HEADER_IMAGE_HEIGHT', apply_filters( 'twentyeleven_header_image_height', 150 ) );
?>
This will change the header height to 970 pixels wide by 150 pixels tall.
this seems to cause WP to throw an error complaining about a “>” on line 594 of the functions.php file if I just past your code at the bottom of the file. Let’s revisit this on Friday.
Yes. This can be a good opportunity to lean to pattern-match in your functions.php file.
Can I suggest you http://www.borgyborgy.net where you can find some free 1000×288 pixel size headers, to customize default TwentyEleven theme. All images are taken by me and provided under a Creative iCommons 3.0 License.
This is pretty cool! You have some nice images there. Thanks for posting.