diff --git a/application/libraries/html_optimize_lib.php b/application/libraries/html_optimize_lib.php
index 562368bd..1480aa62 100644
--- a/application/libraries/html_optimize_lib.php
+++ b/application/libraries/html_optimize_lib.php
@@ -68,7 +68,7 @@ class html_optimize_lib
 
         //请求图片尺寸
         $image_sizes = array();
-        foreach ($request_size as $host => $path) {
+        foreach ($request_size as $host => $path) { //拼接的URL有长度限制，大量的图片一次性请求就会失败，需要分批处理
             $parse_url = "https://{$host}/imagesize.php?photo=" . implode(',', $path);
             $size_data = GET_HTTP($parse_url);
             if (!empty($size_data)) {