Linking image field to an external URL I have a list of images on my node that I want to output wrapped in an anchor tag for linking to external webpages. Images are coming from fields in my content type. I'm not using the Views or the Panels module, and I've edited my page.tpl.php and node.tpl.php files for a rather intricate "About Us" page. 

So how do I do this? I'm using Drupal 7.
You can create a custom field formatter (theme function for fields) where you can define how the image field should be rendered. Here you can add the a tag or any other special markup.

There are a lot of guides on how to do this, both here on the site and on the web, so I won't go into details about how to create a field formatter here, but it's nothing more than a few hooks and a theme function.