[ci skip] Add a changelog entry for #4822
diff --git a/user_guide_src/source/changelog.rst b/user_guide_src/source/changelog.rst
index d41e799..2f08de0 100644
--- a/user_guide_src/source/changelog.rst
+++ b/user_guide_src/source/changelog.rst
@@ -28,6 +28,7 @@
- Fixed a bug (#4808) - :doc:`Database <database/index>` method ``is_write_type()`` only looked at the first line of a queries using ``RETURNING`` with the 'postgre', 'pdo/pgsql', 'odbc' and 'pdo/odbc' drivers.
- Fixed a bug where :doc:`Query Builder <database/query_builder>` method ``insert_batch()`` tried to execute an unsupported SQL query with the 'ibase' and 'pdo/firebird' drivers.
- Fixed a bug (#4809) - :doc:`Database <database/index>` driver 'pdo/mysql' didn't turn off ``AUTOCOMMIT`` when starting a transaction.
+- Fixed a bug (#4822) - :doc:`CAPTCHA Helper <helpers/captcha_helper>` didn't clear expired PNG images.
Version 3.1.0
=============