How to activate slideshow in G2.3 Matrix theme

I try to activate slideshow for all the visitors on my site www.aanimeri.fi. Gallery 2.3. uses Matrix theme and is embedded into Drupal.

There is a text in Gallery Administration Slideshow settings:

"PicLens

Gallery can optionally use a Flash and JavaScript based slideshow from PicLens to provide users with the best possible viewing experience. Gallery can install PicLens for you automatically, or you can choose to use an HTML slideshow.
Version 1.3.1.14221 installed."

However nowhere in the albums nor in the pictures exists any pushbutton nor nothing to start the show. I have uninstalled and installed this PicLens.

Should I do something else somewhere to activate pushbutton or something to have a chance to start the slideshow?

Gallery version (2.3):
PHP version (5.2.9):
Webserver (Apache/2.0.63 (Unix) mod_ssl/2.0.63 OpenSSL/0.9.8c):
Database (MySql 5.0.27):
Activated toolkits (e.g. NetPbm, GD):
Operating system (GNU Linux 2.6.30.5):
Browser (Firefox 3.6.2, MS IE 8.0.6001):
Drupal gallery module gallery-6.x-1.0.tar.gz