Actual zoomable images here: https://www.esa.int/Science_Exploration/Space_Science/Solar_...
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.
They're using OpenSeadragon hosted on a codepen.
https://openseadragon.github.io/
https://codepen.io/Kimtaro88/embed/JjgLyJg/ee2ebbe7041869032...
Leaflet is actually listed at [1], I believe it's totally orthodox :-)
[1] https://en.wikipedia.org/wiki/International_Image_Interopera...
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).
While it works, the resolution is underwhelming and there's no scale.
The Sun's diameter is 109 times that of Earth, though you might as well round up to 110, or down to 100.
1.4 * 10^6 km vs. 14 * 10^3 km.