diff --git a/README.md b/README.md
index b798088..6277bbd 100644
--- a/README.md
+++ b/README.md
@@ -22,3 +22,9 @@ If required, you can mount external volumes. Example:
 ```
 lxc config device add <name> <name>_disk disk source=/dev/vdf path=/mnt/pictures readonly=true raw.mount.options=noload
 ```
+
+Then add it to `group_data/production.py`:
+
+```
+photoprism_originals_src=/mnt/pictures'
+```