Thread:Humphry02/@comment-44975735-20200416090547/@comment-44975735-20200503070355

This isn't correct. The whole point of this solution, which doesn't work perfectly, is that there is only one image in the content: property but it's randomly picked using JavaScript. There is no way to do such a thing with CSS alone.

You should just use what is in the first post and put it anywhere in the MediaWiki:Wikia.js file. It's not really dependent on any other code.