You have to upload the file to a directory on your hosting account, usually /images. Your public_html folder is your website directory which equates to /. Images folder is /images if it exists, you have to create it. After uploading you add the text inside one of your webpages such as:

<a href="http://yourlinkaddr" alt="textifimagedoesntshow"><img src="images/yourfilename.extension" /></a>

This is the most basic form, there's no need for an image size property or an ISMAP property unless you want one large image with multiple "hot spots" on it.