Custom Header in sidebar-page.php

<?php
/**
 * Template Name: Sidebar Template
 * Description: A Page Template that adds a sidebar to pages
 *
 * @package WordPress
 * @subpackage Twenty_Eleven
 * @since Twenty Eleven 1.0
 */

get_header(); ?>

<?php
				// Check to see if the header image has been removed
				$header_image = get_header_image();
				if ( ! empty( $header_image ) ) :
			?>

				<?php
					// The header 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 ) &&
							( /* $src, $width, $height */ $image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), array( HEADER_IMAGE_WIDTH, HEADER_IMAGE_WIDTH ) ) ) &&
							$image[1] >= 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; ?>" id="large_image" alt="" />
				<?php endif; // end check for featured image or standard header ?>

			<?php endif; // end check for removed header image ?>


<?php get_sidebar(); ?>
		<div id="primary">
			<div id="content" role="main">

				<?php while ( have_posts() ) : the_post(); ?>

					<?php get_template_part( 'content', 'page' ); ?>


				<?php endwhile; // end of the loop. ?>

			</div><!-- #content -->
		</div><!-- #primary -->

<?php get_footer(); ?>