Thank you! I've added the infobox to the Element:HYGN page, so we can now start converging to the final design for the element page.
To make the mindless work of creating element pages easier, I can write a script to extract the data from elementdata.c and parse it in the wiki template format. I'll post that on Pastebin sometime today.
powdertoy.co.uk, so I assume British spelling is preferred. (Our wiki uses the same software as Wikipedia, but isn't part of Wikipedia.)
As jacksonmj said, I agree that British spelling should be used on a .co.uk domain.
Fire display mode is a good idea for infobox images, especially with gasses and explosives. I've added a new image for Hydrogen and tweaked the infobox a bit to display the HYGN menu icon above the screenshot in a separate image.
The page is looking good so far. Although, an introduction of some sort (with no header) should probably be placed at the top of the page, much like Wikipedia's page for Hydrogen. Basically, someone could write a summary of the article with a mention of the version added and possibly the name of the user who proposed the idea or developed the source code. If needed, we could compare the properties of the Powder Toy element to the real-life element and mention any notable differences in the introduction.
Sometime today I'll whip up an Examples section template so we can organize the links into a table or something. From the template, you'll be able to paste the save ID (e.g. 673260) and it will parse it as a link: [https://powdertoy.co.uk/Browse/View.html?ID=673260 673260]
The forum uses javascript to fetch some JSON for each thumbnail (e.g. https://powdertoy.co.uk/Browse/View.json?ID=2158) and fills in the information from that, so I guess it could be done client side for the wiki too. That's probably a job for Simon though.