diff --git a/wp-content/themes/twentyseventeen/functions.php b/wp-content/themes/twentyseventeen/functions.php
index b84da6875c..b4b03ed6c7 100644
--- a/wp-content/themes/twentyseventeen/functions.php
+++ b/wp-content/themes/twentyseventeen/functions.php
@@ -580,6 +580,7 @@ add_filter( 'wp_calculate_image_sizes', 'twentyseventeen_content_image_sizes_att
  * Filters the `sizes` value in the header image markup.
  *
  * @since Twenty Seventeen 1.0
+ * @since Twenty Seventeen 3.7 Added larger image size for small screens.
  *
  * @param string $html   The HTML image tag markup being filtered.
  * @param object $header The custom header object returned by 'get_custom_header()'.
@@ -588,7 +589,7 @@ add_filter( 'wp_calculate_image_sizes', 'twentyseventeen_content_image_sizes_att
  */
 function twentyseventeen_header_image_tag( $html, $header, $attr ) {
 	if ( isset( $attr['sizes'] ) ) {
-		$html = str_replace( $attr['sizes'], '100vw', $html );
+		$html = str_replace( $attr['sizes'], '(max-width: 767px) 200vw, 100vw', $html );
 	}
 	return $html;
 }
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 8b59ad54ae..ecfbf10d16 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.6-alpha-58134';
+$wp_version = '6.6-alpha-58135';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.