diff --git a/py/api/image_categories.py b/py/api/image_categories.py
index 77583c57..9b480de2 100644
--- a/py/api/image_categories.py
+++ b/py/api/image_categories.py
@@ -139,10 +139,14 @@ class ImageCategoryRoutesMixin:
             listing = self._favorite_listing(root, files)
             root_key = _favorite_root_key(root)
             # normalize_image_path(root / listed) without a call per file: the
-            # listed spellings are clean relative POSIX paths.
+            # listed spellings are clean relative POSIX paths. Windows abspath
+            # also drops a component's trailing dots and spaces, so it keeps
+            # the call there.
             base = os.path.join(normalize_image_path(str(root)), "")
 
-            def normalized(listed, base=base):
+            def normalized(listed, base=base, root=root):
+                if os.name == "nt":
+                    return normalize_image_path(str(root / listed))
                 return base + os.path.normcase(listed.replace("/", os.sep))
 
             nested = [
diff --git a/tests/test_api_workspace_images.py b/tests/test_api_workspace_images.py
index f2db5fdb..0097e7ca 100644
--- a/tests/test_api_workspace_images.py
+++ b/tests/test_api_workspace_images.py
@@ -1772,6 +1772,17 @@ class TestWorkspaceImages(ImageAPITestCase):
             "SEARCH other USING COVERING INDEX idx_image_file_path (file_path=?)", plan
         )
         self.assertFalse([step for step in plan if step.startswith("SCAN other")])
+        # The category's narrowing clause (#332) keeps every join an index search.
+        sql, params = link_filter_query(
+            "", ["tag-1"], every_link=True, category="cat-3"
+        )
+        with self.api.db.model.get_connection() as conn:
+            plan = [row[3] for row in conn.execute("EXPLAIN QUERY PLAN " + sql, params)]
+        self.assertIn(
+            "SEARCH other USING COVERING INDEX idx_image_file_path (file_path=?)", plan
+        )
+        scans = [step for step in plan if step.startswith("SCAN")]
+        self.assertTrue(all(step.startswith("SCAN gi") for step in scans), plan)
 
     @unittest.skipUnless(
         PERF_BUDGET and not TRACED,