diff --git a/app/db.py b/app/db.py
index 76fc2c0..75674b4 100644
--- a/app/db.py
+++ b/app/db.py
@@ -95,6 +95,13 @@ def init_db(conn):
         conn.execute('ALTER TABLE listings ADD COLUMN seller_type TEXT')
     if 'extras' not in cols:
         conn.execute('ALTER TABLE listings ADD COLUMN extras TEXT')
+    # B1 (photo experience v2): gallery URLs + swipe-time photo index.
+    if 'imgs' not in cols:
+        conn.execute('ALTER TABLE listings ADD COLUMN imgs TEXT')
+    sw_cols = {r['name'] for r in conn.execute(
+        "PRAGMA table_info('swipes')")}
+    if 'last_photo_idx' not in sw_cols:
+        conn.execute('ALTER TABLE swipes ADD COLUMN last_photo_idx INTEGER')
     # P3 tables (idempotent on every call)
     conn.executescript(P3_SCHEMA)
     # P3 event seeding: one round-1 event per existing swipe, copied