diff --git a/wp-content/themes/twentyten/header.php b/wp-content/themes/twentyten/header.php
index 854841c792..3ab1e2b4d2 100644
--- a/wp-content/themes/twentyten/header.php
+++ b/wp-content/themes/twentyten/header.php
@@ -34,11 +34,17 @@
 				<div id="site-description"><?php bloginfo( 'description' ); ?></div>
 
 				<?php
-				if ( is_singular() && has_post_thumbnail( $post->ID ) ) :
-					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; ?>
+					// 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; ?>
 			</div><!-- #branding -->
 
 			<div id="access">