Images are <img src="www.whatever.com/images/pizza.jpg">
Links are a bit odder: <a href= "http://www.whatever.com/articles/onPizza.html">all about pizza</a>
Just don't forget the closing tags (the </a>) after everything except images - they tell the website where to stop. You may have noticed when people here use HTML in subject lines and forget to stop it, and suddenly the entire page under their post is bold, or italic, or what have you. (Until people reply with closing tags embedded into their subject lines, anyways.)