Is this a solution they rolled on their own? Cause it's abysmal. I've seen Leaflet being used for gigapixel images and it's great, even if it seems unorthodox.

While it works, the resolution is underwhelming and there's no scale.

If you scroll down to the image carousel/gallery and click on an image, it directs you to a page where you can download a high-res jpeg (~100mb for the ultraviolet one).

not sure if its the server traffic or browser limitations but zooming and panning are quite slow and somewhat dent the awesomeness of this.