diff --git a/wp-includes/media.php b/wp-includes/media.php
index ef6baa7bc2..1c8387b141 100644
--- a/wp-includes/media.php
+++ b/wp-includes/media.php
@@ -1027,6 +1027,14 @@ function wp_calculate_image_srcset( $size_array, $image_src, $image_meta, $attac
 	$upload_dir = wp_get_upload_dir();
 	$image_baseurl = trailingslashit( $upload_dir['baseurl'] ) . $dirname;
 
+	/*
+	 * If currently on HTTPS, prefer HTTPS URLs when we know they're supported by the domain
+	 * (which is to say, when they share the domain name of the current request).
+	 */
+	if ( is_ssl() && 'https' !== substr( $image_baseurl, 0, 5 ) && parse_url( $image_baseurl, PHP_URL_HOST ) === $_SERVER['HTTP_HOST'] ) {
+		$image_baseurl = set_url_scheme( $image_baseurl, 'https' );
+	}
+
 	/*
 	 * Images that have been edited in WordPress after being uploaded will
 	 * contain a unique hash. Look for that hash and use it later to filter
diff --git a/wp-includes/version.php b/wp-includes/version.php
index ff416ba399..9f0ad5dc9e 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.5-beta3-37021';
+$wp_version = '4.5-beta3-37022';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.