diff --git a/README.md b/README.md
index 67171a8..a2386cc 100644
--- a/README.md
+++ b/README.md
@@ -51,8 +51,13 @@ exec_always DISPLAY=:0 i3-wallpaper-manager /path/to/config.yaml
 
 If you wish to use a program other than `feh`, set the `callback` parameter by specifying the path to your script.
 
+```yaml
+callback: /path/to/custom.sh
+```
+
 ```bash
 #!/bin/sh
+# /path/to/custom.sh
 
 SCREEN_1="$1"
 WALLPAPER_1="$2"
@@ -60,5 +65,5 @@ WALLPAPER_1="$2"
 SCREEN_2="$3"
 WALLPAPER_2="$4"
 
-# ...
+...
 ```