There are two types of gifs: gif87a (non-transparent) and gif89a (transparent). When you make a transparent gif, you choose a color to be the "background" color. You'll see the background color of your browser in place of the background color you chose .
Transparent gifs are just images that have one color as a background color. Any part of the image that is the background color doesn't show up. It just makes the images and your overall page look much better. You can use one of the following software to create a transparent GIF (version 89a).
