When it comes to web design, you want your clients to look at the layout of the site, and how the site handles the content. It can be easy to get caught up reading the text, so designers usually fill it in with Lorem Ipsum text. It's great, I love it. But what about images? Surely, you've got to demonstrate to your clients that the image upload feature of the content management system works, show them where they can expect the image to be once it's uploaded, and to know that an image can even go there, all while not distracting them with the image that you happened to have on your desktop that you decided you use just because it was closest one at the moment.