All three are images created by Mark Ferrari (a pixel art OG who worked on stuff like Monkey Island), but in the original they're not gifs because they're actually static images with color cycling / palette shifting. His website links to demos hosted at
http://www.effectgames.com/demos/worlds/http://www.effectgames.com/demos/canvascycle/If you want to learn more, I found his talk at GDC 2016 surprisingly captivating
https://www.youtube.com/watch?v=aMcJ1Jvtef0 
