I believe that might be made possible if there is a post thumbnail on that page is uses it. Here’s the pertinent code from wp-content/themes/twentyten/header.php:
<?php
// Retrieve the dimensions of the current post thumbnail -- no teensy header images for us!
$image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'post-thumbnail');
list($src, $width, $height) = $image;
// Check if this is a post or page, if it has a thumbnail, and if it's a big one
if ( is_singular() && has_post_thumbnail( $post->ID ) && $width >= HEADER_IMAGE_WIDTH ) :
// Houston, we have a new header image!
echo get_the_post_thumbnail( $post->ID, 'post-thumbnail' );
else : ?>
<img src="<?php header_image(); ?>" width="<?php echo HEADER_IMAGE_WIDTH; ?>" height="<?php echo HEADER_IMAGE_HEIGHT; ?>" alt="" />
<?php endif; ?>
The problem is that there is no place to set the post-thumbnail, got the featured image, but not the post-thumbnail setting.
Thanks for reply
On a clean 3.0-beta install, was able to upload an image to the About page, clicked on the use as featured image and it used that image in the header when displaying that page.
