Because inserting cat pictures into your projects should be easy.
cat-a-pult is a frictionless way of insert placeholder images into your projects as you are designing and testing them. Specifically pictures of cats. MORE specifically, pictures of cats from the wonderfull placekitten.com.
Download the minified cat-a-pult file and include it in your webpage (for now, be sure you have JQuery loaded as well.)
<script src="js/cat-a-pult.min.js"></script>
From there, any div with a class that begins with the word "cat" is automatically filled with an image element that uses the div's declared height and width as parameters for a placekitten URL that returns a cat photo to fill your element.
Cats. All the time. It's that simple.