Does Ignite Gallery work in PHP 8.1?
The current version of Ignite Gallery does not work in PHP 8.1
PHP 8.1 was released on 25th of November 2021.
A new version gallery version that supports PHP 8.1 will be released in January or February 2022.
You can see you PHP version in Joomla:
Please go to your webhosting control panel, and choose use PHP 8.0 or PHP 7: