Index: wp-content/themes/twentytwelve/content-image.php
===================================================================
--- wp-content/themes/twentytwelve/content-image.php	(revision 21673)
+++ wp-content/themes/twentytwelve/content-image.php	(working copy)
@@ -14,7 +14,9 @@
 		</div><!-- .entry-content -->
 
 		<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 echo get_the_date(); ?></h2>
+			<a href="<?php the_permalink(); ?>" title="<?php echo esc_attr( sprintf( __( 'Permalink to %s', 'twentytwelve' ), the_title_attribute( 'echo=0' ) ) ); ?>" rel="bookmark">
+				<h1><?php the_title(); ?></h1>
+				<h2><time class="entry-date" datetime="<?php echo esc_attr( get_the_date( 'c' ) ); ?>" pubdate><?php the_date(); ?></time></h2>
+			</a>
 		</footer><!-- .entry-meta -->
 	</article><!-- #post -->
Index: wp-content/themes/twentytwelve/style.css
===================================================================
--- wp-content/themes/twentytwelve/style.css	(revision 21673)
+++ wp-content/themes/twentytwelve/style.css	(working copy)
@@ -975,6 +975,9 @@
 	font-size: 0.785714286rem;
 	line-height: 2.181818182;
 }
+article.format-image footer a h2 {
+	font-weight: normal;
+}
 
 /* Link posts */
 article.format-link header {