diff --git a/immich-compose.yml b/immich-compose.yml
index 23e068f..5b1909e 100644
--- a/immich-compose.yml
+++ b/immich-compose.yml
@@ -12,8 +12,10 @@ services:
     volumes:
       - ${UPLOAD_LOCATION}:/usr/src/app/upload
       - /etc/localtime:/etc/localtime:ro
-      # Optional: Mount an existing photo library as a read-only external library
-      # - ${EXTERNAL_LIBRARY_PATH}:/mnt/external:ro
+      # Read-only source folders for Immich External Libraries / PhotoPrism migration testing
+      - /mnt/HomeStorage/Photos/Originals:/mnt/external/photoprism-photos-originals:ro
+      - /mnt/HomeStorage/Applications/PhotoPrism/Originals:/mnt/external/photoprism-app-originals:ro
+      - /mnt/HomeStorage/Media/OurPictures:/mnt/external/ourpictures:ro
     environment:
       DB_HOSTNAME: postgres
       DB_USERNAME: ${DB_USERNAME}