Update: for anyone else having this issue, I had to go to the Manage Display tab for that content type and enable the custom field to be visible on the teaser.
I am having some issues with custom field content only displaying on the individual node. I have created a new field called field_second_image for the Article content type. I am calling it right under the regular field_image with print render($content['field_second_image']); in my node--article.tpl.php file. On the actual article node both images display properly. However, on a taxonomy list page or the custom article view page I have created, the second image does not show up. I think this relates to the general issue I've been having getting custom field content to display on pages other than the individual node page. Is there something I'm completely missing about getting this content to appear on other pages? Any help would be greatly appreciated, thank you.