The picture above is a single <div> element. Each pixel is a box-shadow of 1px height and width. CSS generated by a python script. Github repo here. Inspired by Lynn Fisher.

There is literally no practical use for this as it stands. Trust me, I spent at least a minute trying to think of some obscure fantastical use-case where you'd need 4.6MB of CSS instead of 50KB of jpeg. If you can think of one, let me know.

Warning: Don't click that div in the Inspect Element pane, unless you have hoards of RAM. It'll try to load all the styles and hang. If you want a smaller example whose source you can inspect, look at this smaller example of my friend.