I think figgis may be responding in a sarcastic way and trying to point out that those are not animated gifs, but are actual HTML page elements, animated with CSS. If you view on desktop and use a browser DOM inspector (like Chrome Dev Tools) you can verify that this is the case.

To be honest I'm quite impressed that NYTimes went this length to create these technical widgets. Do they have software engineers or web developers working in conjunction with journalists on articles like these? Seems like a relatively high cost of production.

Although I'm not a fan, I have to say in this case it does do its job quite well, which is to demonstrate how having twitter news would feel like back in the 1968s~ time.