Index: wp-content/themes/twentytwelve/content-image.php
===================================================================
--- wp-content/themes/twentytwelve/content-image.php	(revision 21653)
+++ wp-content/themes/twentytwelve/content-image.php	(working copy)
@@ -15,6 +15,6 @@
 
 		<footer class="entry-meta">
 			<h1><a href="<?php the_permalink(); ?>" title="<?php echo esc_attr( sprintf( __( 'Permalink to %s', 'twentytwelve' ), the_title_attribute( 'echo=0' ) ) ); ?>" rel="bookmark"><?php the_title(); ?></a></h1>
-			<h2><?php the_date(); ?></h2>
+			<h2><a href="<?php the_permalink(); ?>" title="<?php the_time(); ?>" rel="bookmark"><time class="entry-date" datetime="<?php echo get_the_date( 'c' ); ?>" pubdate><?php the_date(); ?></time></a></h2>
 		</footer><!-- .entry-meta -->
 	</article><!-- #post -->