diff --git a/wp-content/themes/twentyfourteen/content-featured-post.php b/wp-content/themes/twentyfourteen/content-featured-post.php
index 34747dcc74..b838b33208 100644
--- a/wp-content/themes/twentyfourteen/content-featured-post.php
+++ b/wp-content/themes/twentyfourteen/content-featured-post.php
@@ -13,9 +13,9 @@
 	<?php
 		if ( has_post_thumbnail() ) :
 			if ( 'grid' == get_theme_mod( 'featured_content_layout' ) )
-				the_post_thumbnail( 'post-thumbnail' );
+				the_post_thumbnail();
 			else
-				the_post_thumbnail( 'post-thumbnail-full-width' );
+				the_post_thumbnail( 'twentyfourteen-full-width' );
 		endif;
 	?>
 	</a>
diff --git a/wp-content/themes/twentyfourteen/functions.php b/wp-content/themes/twentyfourteen/functions.php
index d485918d80..50efd1b264 100644
--- a/wp-content/themes/twentyfourteen/functions.php
+++ b/wp-content/themes/twentyfourteen/functions.php
@@ -66,8 +66,8 @@ function twentyfourteen_setup() {
 
 	// Enable support for Post Thumbnails, and declare two sizes.
 	add_theme_support( 'post-thumbnails' );
-	add_image_size( 'post-thumbnail-full-width', 1038, 576, true );
-	add_image_size( 'post-thumbnail', 672, 372, true );
+	set_post_thumbnail_size( 672, 372, true );
+	add_image_size( 'twentyfourteen-full-width', 1038, 576, true );
 
 	// This theme uses wp_nav_menu() in two locations.
 	register_nav_menus( array(
diff --git a/wp-content/themes/twentyfourteen/inc/template-tags.php b/wp-content/themes/twentyfourteen/inc/template-tags.php
index e93b927dab..ed9c017770 100644
--- a/wp-content/themes/twentyfourteen/inc/template-tags.php
+++ b/wp-content/themes/twentyfourteen/inc/template-tags.php
@@ -174,9 +174,9 @@ function twentyfourteen_post_thumbnail() {
 	<div class="post-thumbnail">
 	<?php
 		if ( ( ! is_active_sidebar( 'sidebar-2' ) || is_page_template( 'page-templates/full-width.php' ) ) && ! wp_is_mobile() )
-			the_post_thumbnail( 'post-thumbnail-full-width' );
+			the_post_thumbnail( 'twentyfourteen-full-width' );
 		else
-			the_post_thumbnail( 'post-thumbnail' );
+			the_post_thumbnail();
 	?>
 	</div>
 
@@ -185,9 +185,9 @@ function twentyfourteen_post_thumbnail() {
 	<a class="post-thumbnail" href="<?php the_permalink(); ?>" rel="<?php the_ID(); ?>">
 	<?php
 		if ( ( ! is_active_sidebar( 'sidebar-2' ) || is_page_template( 'page-templates/full-width.php' ) ) && ! wp_is_mobile() )
-			the_post_thumbnail( 'post-thumbnail-full-width' );
+			the_post_thumbnail( 'twentyfourteen-full-width' );
 		else
-			the_post_thumbnail( 'post-thumbnail' );
+			the_post_thumbnail();
 	?>
 	</a>
 
diff --git a/wp-content/themes/twentyfourteen/inc/widgets.php b/wp-content/themes/twentyfourteen/inc/widgets.php
index 49be068b3b..73c95ffb57 100644
--- a/wp-content/themes/twentyfourteen/inc/widgets.php
+++ b/wp-content/themes/twentyfourteen/inc/widgets.php
@@ -158,7 +158,7 @@ class Twenty_Fourteen_Ephemera_Widget extends WP_Widget {
 									$total_images = count( $images );
 
 									if ( has_post_thumbnail() ) :
-										$post_thumbnail = get_the_post_thumbnail( get_the_ID(), 'post-thumbnail' );
+										$post_thumbnail = get_the_post_thumbnail();
 									elseif ( $total_images > 0 ) :
 										$image          = array_shift( $images );
 										$post_thumbnail = wp_get_attachment_image( $image, 'post-thumbnail' );