Index: functions.php
===================================================================
--- functions.php	(revision 24244)
+++ functions.php	(working copy)
@@ -346,8 +346,13 @@
 		<h1 class="screen-reader-text"><?php _e( 'Post navigation', 'twentythirteen' ); ?></h1>
 		<div class="nav-links">
 
-			<?php previous_post_link( '%link', _x( '<span class="meta-nav">&larr;</span> %title', 'Previous post link', 'twentythirteen' ) ); ?>
-			<?php next_post_link( '%link', _x( '%title <span class="meta-nav">&rarr;</span>', 'Next post link', 'twentythirteen' ) ); ?>
+			<?php if ( is_rtl() ) : ?>
+				<?php previous_post_link( '%link', _x( '<span class="meta-nav">&rarr;</span> %title', 'Previous post link', 'twentythirteen' ) ); ?>
+				<?php next_post_link( '%link', _x( '%title <span class="meta-nav">&larr;</span>', 'Next post link', 'twentythirteen' ) ); ?>
+			<?php else : ?>
+				<?php previous_post_link( '%link', _x( '<span class="meta-nav">&larr;</span> %title', 'Previous post link', 'twentythirteen' ) ); ?>
+				<?php next_post_link( '%link', _x( '%title <span class="meta-nav">&rarr;</span>', 'Next post link', 'twentythirteen' ) ); ?>
+			<?php endif; ?>
 
 		</div><!-- .nav-links -->
 	</nav><!-- .navigation -->
Index: image.php
===================================================================
--- image.php	(revision 24244)
+++ image.php	(working copy)
@@ -82,8 +82,8 @@
 
 				<div class="entry-content">
 					<nav id="image-navigation" class="navigation image-navigation" role="navigation">
-						<span class="nav-previous"><?php previous_image_link( false, __( '<span class="meta-nav">&larr;</span> Previous', 'twentythirteen' ) ); ?></span>
-						<span class="nav-next"><?php next_image_link( false, __( 'Next <span class="meta-nav">&rarr;</span>', 'twentythirteen' ) ); ?></span>
+						<span class="nav-previous"><?php previous_image_link( false, sprintf( __( '<span class="meta-nav">%s</span> Previous', 'twentythirteen' ), is_rtl() ? '&rarr;' : '&larr;' ) ); ?></span>
+						<span class="nav-next"><?php next_image_link( false, sprintf( __( 'Next <span class="meta-nav">%s</span>', 'twentythirteen' ), is_rtl() ? '&larr;' : '&rarr;' ) ); ?></span>
 					</nav><!-- #image-navigation -->
 
 					<div class="entry-attachment">