Piwik plugin for Zenphoto
Download and install
Download and unzip the zip archive, then copy the file piwik.php into the zenphoto plugin directory (zenphoto/zp-core/plugins/).
Configuration
You need to activate the plugin first. Go to the administration panel of zenphoto, click on "plugins", and check the checkbox on the left of the piwik plugin.
From the menu "options > plugins configuration", you can modify some parameters if you need.