diff --git a/modules/services/nextcloud.nix b/modules/services/nextcloud.nix
index eb2e14e..d615903 100644
--- a/modules/services/nextcloud.nix
+++ b/modules/services/nextcloud.nix
@@ -70,6 +70,10 @@ in
       paths = [
         config.services.nextcloud.home
       ];
+      exclude = [
+        # image previews can take up a lot of space
+        "${config.services.nextcloud.home}/data/appdata_*/preview"
+      ];
     };
   };
 }