diff --git a/readme.md b/readme.md
index ae377b1..e6d7658 100644
--- a/readme.md
+++ b/readme.md
@@ -343,6 +343,7 @@ grep -i "Query" file.txt
 
 ```shell
 imgcat image.png
+# Note: requires iTerm2 terminal.
 ```
 
 ## show disk size