Index: wp-content/themes/twentythirteen/image.php
===================================================================
--- wp-content/themes/twentythirteen/image.php	(revision 24423)
+++ wp-content/themes/twentythirteen/image.php	(working copy)
@@ -20,7 +20,7 @@
 					<div class="entry-meta">
 						<?php
 							$published_text = __( '<span class="attachment-meta">Published on <time class="entry-date" datetime="%1$s">%2$s</time> in <a href="%3$s" title="Return to %4$s" rel="gallery">%5$s</a></span>', 'twentythirteen' );
-							$post_title = get_the_title( $post->post_parent );
+							$post_title     = get_the_title( $post->post_parent );
 							if ( empty( $post_title ) || 0 == $post->post_parent )
 								$published_text = '<span class="attachment-meta"><time class="entry-date" datetime="%1$s">%2$s</time></span>';
 
@@ -32,14 +32,16 @@
 								$post_title
 							);
 
-							$metadata = wp_get_attachment_metadata();
-							printf( '<span class="attachment-meta full-size-link"><a href="%1$s" title="%2$s">%3$s (%4$s &times; %5$s)</a></span>',
-								esc_url( wp_get_attachment_url() ),
-								esc_attr__( 'Link to full-size image', 'twentythirteen' ),
-								__( 'Full resolution', 'twentythirteen' ),
-								$metadata['width'],
-								$metadata['height']
-							);
+							if ( ! post_password_required( $post->post_parent ) ) :
+								$metadata = wp_get_attachment_metadata();
+								printf( '<span class="attachment-meta full-size-link"><a href="%1$s" title="%2$s">%3$s (%4$s &times; %5$s)</a></span>',
+									esc_url( wp_get_attachment_url() ),
+									esc_attr__( 'Link to full-size image', 'twentythirteen' ),
+									__( 'Full resolution', 'twentythirteen' ),
+									$metadata['width'],
+									$metadata['height']
+								);
+							endif;
 
 							edit_post_link( __( 'Edit', 'twentythirteen' ), '<span class="edit-link">', '</span>' );
 						?>
Index: wp-content/themes/twentythirteen/functions.php
===================================================================
--- wp-content/themes/twentythirteen/functions.php	(revision 24423)
+++ wp-content/themes/twentythirteen/functions.php	(working copy)
@@ -433,6 +433,13 @@
  */
 function twentythirteen_the_attached_image() {
 	$post                = get_post();
+
+	// If post parent is password protected, show the form and bail.
+	if ( post_password_required( $post->post_parent ) ) {
+		echo get_the_password_form( $post->post_parent );
+		return;
+	}
+
 	$attachment_size     = apply_filters( 'twentythirteen_attachment_size', array( 724, 724 ) );
 	$next_attachment_url = wp_get_attachment_url();