Steps to reproduce the issue

In the backend:

1. Navigate to Menu Home dashboard
2. Click Global configuration, in TAB "Server", set Error Reporting to "Maximum".
3. Navigate to Menu System
4. Click Administrator Template Styles, open your active style. In my case it is "Atum - Default".
5. In TAB "Image Settings", Select a "Brand Large" image, leave Image description empty and check the "No Description" box.
6. Select a "Brand Small" image, leave Image description empty and check the "No Description" box.
7. Click SAVE.

Expected result

There is no PHP deprecation warning.

Actual result

There are two PHP deprecation warnings:

Deprecated
: htmlspecialchars(): Passing null to parameter #1 ($string) of type string is deprecated in
E:\joomla\4.2.2\administrator\templates\atum\index.php
on line
56

Deprecated
: htmlspecialchars(): Passing null to parameter #1 ($string) of type string is deprecated in
E:\joomla\4.2.2\administrator\templates\atum\index.php
on line
59

System information (as much as possible)

Installed Joomla 4.2.0 and updated it to 4.2.2
mysql 10.4.24-MariaDB
Apache/2.4.53 (Win64) OpenSSL/1.1.1n PHP/8.1.6
Joomla! 4.2.2 Stable [ Uaminifu ] 16-August-2022 13:05 GMT

Additional comments