Update: partial solution.
Article on the wiki: http://www.magentocommerce.com/wiki/adding_lightbox_to_magento_v2
It’s a bit of a pain to install - there’s a file location not specified in the instructions:
instructions say ”- in page/html/head.phtml, find”
the file is here (if Magento is installed as root): app/design/adminhtml/default/default/template/page/head.phtml
There’s a mention of this setup being packaged & distributed as an extension (i.e. automatic install). Either try the extension, or carefully follow the directions.
So, now I have a neat “Lightbox” gallery effect. STILL don’t know how to add more images (i.e. #5, 6, 7, etc.)
Will post an update when I figure it out… or hopefully someone can point me in the right direction.