diff --git a/inc/Data/Driver/Metadata/PngExifReader.php b/inc/Data/Driver/Metadata/PngExifReader.php
index f56471cb..f77693ed 100644
--- a/inc/Data/Driver/Metadata/PngExifReader.php
+++ b/inc/Data/Driver/Metadata/PngExifReader.php
@@ -142,7 +142,7 @@ class PngExifReader implements ExifReader {
 		if ($fd === false) {
 			return self::ERR_COULD_NOT_OPEN;
 		}
-		return self::tryReadPngChunks($fd);
+		$ret = self::tryReadPngChunks($fd);
 		\fclose($fd);
 		if ($ret < 1 || $ret > 9) {
 			return null;