This is an archive of former official plugins. There were once officially supported and included in the release package.
Readme files or script comments will describe their use and these plugins are also listed on our site's extensions section: http://www.zenphoto.org/news/category/extensions
Please remember that these plugins are provided for your use and education but are not actively supported and maintained by the ZenphotoCMS team. Many of these plugins are quite old and may not work correctly with current ZenphotoCMS versions.
Although we don't actively support these, we welcome contributions via pull requests or even taking over development. Please read the contributor guidelines: http://www.zenphoto.org/news/general-contributor-guidelines#providing-themes-and-plugins
Plugins are folders found in the plugins folder. They should be placed in the plugins folder of your installation.
Note that what should be copied is the content of the folder. This will typically be a PHP script and a like-named folder with other content. The PHP script needs to be in the root of the "plugins" folder. http://www.zenphoto.org/news/using-plugins-and-third-party-features#installing-third-party-plugins
Most of the contents is GPL v2 or later licensed, e.g. those created by current or former ZenphotoCMS team members. But since there are also third party solutions collected please see each tool for its exact licensing.