Expandoo expands images when they are clicked, much like a lightbox, but without opening anything new.
In the WordPress media uploader, there will be a new option in the "Link to" dropdown named "Expandoo", select this to activate the plugin for that image as it's inserted into the editor. Adding the class ".expandoo" to any image will also activate that image for the plugin.
The following data attributes can be used to change the default settings.
<img src="myimage.png" data-speed="1000" data-parent="#parent_id" data-maxwidth="300" class="expandoo" />