I'd like to show one random image from one gallery. Can I do that?
On the NGG site I found the announcement of a "random" shortcode, but it does not list a gallery option. The demo page has broken images. http://www.nextgen-gallery.com/two-new-shortcodes/
The page about everything I want to know about galleries doesn't say how to invoke the random images which are mentioned.
The Documentation page is a table of contents with a link to "Shortcodes"... which returns to the same Documentation page.