diff --git a/fawkes/README.md b/fawkes/README.md
index b69f649..126c644 100644
--- a/fawkes/README.md
+++ b/fawkes/README.md
@@ -13,6 +13,7 @@ If you are a developer or researcher planning to customize and modify on our exi
 * Open [terminal](https://support.apple.com/guide/terminal/open-or-quit-terminal-apd5265185d-f365-44cb-8b09-71a064a42125/mac) and change directory to fawkes (the unzipped folder). 
 * (If your MacOS is Catalina) Run `sudo spctl --master-disable` to enable running apps from unidentified developer. 
 * Run `./fawkes -d IMAGE_DIR_PATH -m low` to generate cloak for images in `IMAGE_DIR_PATH`. 
+* When the cloaked image is generated, it will output a `*_low_cloaked.png` image in `IMAGE_DIR_PATH`. The generation takes ~40 seconds per image depending on the hardware. 
 * More details on the optional parameters check out the [github repo](https://github.com/Shawn-Shan/fawkes/tree/master/).