Hi, forward your question henry.winky@gmail.com
He can help you!
If the plugin is not a standard plugin, you will need to download it and place it in the plugins directory. If you're using 1.2.6, this directory will be zp-core/plugins. If you're using 1.2.7, you should put it in the plugins directory in the root of your zenphoto installation.
Then you simply activate the plugin in the zenphoto back-end from the Plugins tab.