How do you programmatically hide a field based on another field on a custom content type? I have built a custom content type that has a boolean field called 'Hide images'. There is also an images field that displays all images at the bottom of the node. I'd like to setup a way so that depending on the 'Hide images' field I can decide whether to display the images field. Is there a way to edit this via a template?

I saw in page--node--contenttype.tpl.php that I could render($page['content']); but I couldn't actually see how I could choose what content to display.
In your template, instead of rendering the entire content array, you can break it down to print each individual item separately.  Then, you could wrap the printing of the images in a statement that checks if the boolean value is true/false.

&lt;?php if ($content['field_boolean_hide_images'] === FALSE): ?&gt;
  &lt;?php print render($content['field_image']); ?&gt;
&lt;?php endif; ?&gt;


This is just an example and shouldn't be used verbatim.

Also, to create a template for your content type, it would be node--yourContentType.tpl.php rather than a page template override.