Why is it flashing a bluescreen at me every 25 seconds?

https://oldestsearch.com/blue.png

Code from their site:

    setInterval(() => {
      app.style.backgroundImage = "url(https://oldestsearch.com/blue.png)";
      setTimeout(() => {
        app.style.backgroundImage = "url(https://oldestsearch.com/bg.png)";
      }, 200);
    }, 25000);