‘Embed’ here is what WordPress calls the ability to add a URL of a site on its own line in a post or page, and for a nice rendering of the site at that URL to be provided automatically. It works with core WordPress with sites like Youtube and Flickr, and somewhat for random other sites if they provide the right metadata. Piwigo does not yet provide particularly rich metadata (there are some ideas to do so, though), but anyway it’s nicer to be able to do something more complicated that uses the Piwigo API.
As a first hack at this, my plugin just shows the medium-sized image, with title below and description as the tooltip, and the image linked to the page on the Piwigo site. I plan on introducing caching, and perhaps some nicer display (dates, comment count, etc.). Ideas welcome!