[Solved] Need some help with displaying a random thumbnail from 2+ galleries

[Alb]

Hello!
I use the following code to display a random thumbnail to my website.

PHP Code:

<?php get_i18n_gallery('gallery1',array('url'=>'gallery1', 'thumb'=>'random')); ?>

This code selects a random picture from my gallery1 and display the thumbnail.
I want to select random pictures from 2 or more galleries and to display the random thumbnail.
How can I integrate gallery2, gallery3... in this query?
I tried with array but didn't succeed, maybe I didn't make the correct array code. Any suggestion?
Thanks