erAck wrote:

There's no extension for a full backup. Dump the database to a logical backup file, using the MySQL utility mysqldump or something like phpMyAdmin or Adminer. Then backup that file and all of your Piwigo installation directory tree including images under galleries/ and upload/. You may omit generated content under the _data/ directory. Use any file backup tool suitable for you, or tar.gz everything and then copy that off-server.

My personal recommendation for file backups is BorgBackup or if you want to backup to cloud storage or an online service then maybe restic. Both though are usually not available with web hosting services.

Wow, what an informative answer, thank you as much as I can :).