diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 6b6a044bff..a3e813dd61 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -2366,7 +2366,8 @@ function wp_get_image_mime( $file ) {
 	 */
 	try {
 		if ( is_callable( 'exif_imagetype' ) ) {
-			$mime = image_type_to_mime_type( exif_imagetype( $file ) );
+			$imagetype = exif_imagetype( $file );
+			$mime = ( $imagetype ) ? image_type_to_mime_type( $imagetype ) : false;
 		} elseif ( function_exists( 'getimagesize' ) ) {
 			$imagesize = getimagesize( $file );
 			$mime = ( isset( $imagesize['mime'] ) ) ? $imagesize['mime'] : false;
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 552bda8be2..552352449f 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.7.4-alpha-40402';
+$wp_version = '4.7.4-alpha-40403';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.