Every subdomain gets its own gif, so you can query by url (i.e. https://hackernews.gif.so). Anyone can change the image that loads on a given page... one day I'll make it a voting system. Useful for quickly putting a gif of an arbitrary thing in chat apps as most will unfurl the image directly. If you just want a static image, use https://jpg.so instead.

Someone else made this years ago and hosted it at jpg.to. That went down a while ago and I recreated it because it is fun and sometimes useful and not owned by Meta.