In your include/constants.php, is the LOUNGE_TABLE constant there? Maybe not all of your files were upgraded?

if (!defined('LOUNGE_TABLE'))
  define('LOUNGE_TABLE', $prefixeTable.'lounge');

Helo I have an issue with "Personal Favicon". I received the following message :
Warning: Parameter 2 to Favicon() expected to be a reference, value given in /var/www/html/photos/include/smarty/libs/sysplugins/smarty_internal_runtime_filterhandler.php on line 63

I've started with Piwigo 12 then upgraded to 12.1.0 with no problems but be warned, all plugins aren't compatible with this version so I suggest to test it out before you launch your gallery to public.

A follow-up my problem reported earlier in this thread.  We were able to solve the problem by adding the missing table based on the schema found here:

[Github] Piwigo file install/piwigo_structure-mysql.sql

All that was necessary was:

CREATE TABLE `piwigo_lounge` (
  `image_id` mediumint(8) unsigned NOT NULL DEFAULT '0',
  `category_id` smallint(5) unsigned NOT NULL DEFAULT '0',
  PRIMARY KEY (`image_id`,`category_id`)
) ENGINE=MyISAM;

After that the site worked. Then we upgraded from 12.1.0 to 12.2.0 without any errors.