XHTML & CSS Tutorial - Images
The image tag lets you display images on your webpage.
<img src="http://img530.imageshack.us/img530/6599/mjbaig4824c9aa5tx4.png" alt="Stewie Griffin!" />
The src= is like the href= on a hyperlink its the loction of the picture you want to show. The alt= is important, it will show the text "Stewie Griffin!" if the image fails to load.
You can combine hyperlinks and images together to make a picture clickable.
<a href="http://www.familyguy.com"><img src="http://img530.imageshack.us/img530/6599/mjbaig4824c9aa5tx4.png" alt="Stewie" /></a>