Index: src/wp-includes/media.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- src/wp-includes/media.php	(revision 33525)
+++ src/wp-includes/media.php	(revision )
@@ -2762,8 +2762,15 @@
 	}
 
 	$attached_file = get_attached_file( $attachment->ID );
-	if ( file_exists( $attached_file ) ) {
+
+	$bytes = false;
+	if ( isset( $meta['filesize'] ) ) {
+		$bytes = $meta['filesize'];
+	} else if ( file_exists( $attached_file ) ) {
 		$bytes = filesize( $attached_file );
+	}
+
+	if ( ! empty( $bytes ) ) {
 		$response['filesizeInBytes'] = $bytes;
 		$response['filesizeHumanReadable'] = size_format( $bytes );
 	}