This is a demo of using the CSS3 Box-Shadow in a variety of different ways. Check out the examples below, and then check out the tutorial here; where you can see how to write the CSS code to create these different effects.

The first example is actually the div that this text is in. See the shadow behind the div? No images are used for this, only pure CSS. This is an example of a shadow with zero offset to the side, just straight back. You can see below some examples of shadows with an offset, and even color.

One of the interesting things to notice is how on an image with a round border the shadow even wraps around it in the round shape. This opens up the door for a ton of creative effects.