Someone in my webhost forum posted a link to a page with a great example of javascript code coolness: Highslide JS
I have added the code to my gallery. Now, when clicking on the thumbnails, a full size version of the image will show up right on the page, instead of going to the intermediate page that shows the full size image. To preserve the ability to access image details, the caption in the popup includes a link to the page.
Once I decide this is stable, I’ll post instructions in Coppermine forums.