What's not there yet are the images. But there are little boxes that appear to be pressed into the page just waiting for the image to arrive. Sometimes there's even text in the box telling you what's going to go in the box. Actually, it's not all that tough to do. The commands are denoting the image's height and width in pixels.
Pixels are little colored dots.
If you put enough of them close together, they form a picture. Those of you there with vivid imaginations know that the height and width commands can be used to change the shape of an image. If the image is really 50X50 and you put in height and width commands of 150 and 10, you will distort the picture pretty well. For an example, see the Manipulating Images primer. A better way to use the commands is to denote the exact height and width of an image.