How come Automator can't find images on sites like this:?

I want all of these brains in a folder because I'd like to see them in a 3d stack. I've been following steps outlined as the top answer of this thread: https://apple.stackexchange.com/questions/121649/how-to-download-a-webpages-all-images-at-once?newreg=ca08ffba925d4554a19e9332111d6bc5 And indeed this simple three step action works as it should for most other sites I've tried it on. So what's going on here? I assume it has something to do with the fact that they're thumbnails contained in some sort of mysterious grid. (I am a novice if my terminology hadn't tipped you off already). I'd be fine downloading the thumbnails. I'd actually prefer small images as I intend to stack these all into a 3d volume. My computer would not appreciate the full size versions in this application. Any workarounds, clues, hints are greatly appreciated. Maybe a good fundamental thing to learn would be what the "impervious mystery image grid" is really called.