If you include an <img tag inside the opening and closing parts of
a link tag, <a>, that image serves as a clickable hot spot for the
link itself:
<a href="index.html"><img src="arrow.gif"></a>
If you include both an image and text in the <a>...</a> tags,
the image and text become hot spots pointing to the same page:
<a href="index.html"><img src="arrow.gif">
Back to Main Page </a>
