diff --git a/server/apps/edu/views.py b/server/apps/edu/views.py
index 94d859c..bbcabab 100644
--- a/server/apps/edu/views.py
+++ b/server/apps/edu/views.py
@@ -150,8 +150,14 @@ class CertificateViewSet(CreateUpdateCustomMixin, ModelViewSet):
         # Fetch the objects to update
         Certificate.objects.filter(id__in=ids).update(**updates)
         queryset = Certificate.objects.filter(id__in=ids)
-        thread = threading.Thread(target=make_img_x, args=(queryset,))
-        thread.start()
+        threads = []
+        for obj in queryset:
+            thread = threading.Thread(target=make_img_x, args=(obj,))
+            threads.append(thread)
+            thread.start()
+
+        for thread in threads:
+            thread.join()
         # # Update the objects
         # for obj in objects:
         #     # for field, value in updates.items():