So we tried to make our own template, but we don't want to use the click-able picture at the top of the email. We have searched and searched but haven't been able to find anything.
There are a number of possible approaches to take with regard to the header image in an email blast.
If you're working on developing your own custom email theme, you'll want to look for the lines of code that render the image and either modify or remove them. For example, the code in the image below is from a custom version of the "Basic with logo" theme. If your custom theme is based off of another of our public themes, this code may look different in your case.
Removing the lines of code wrapped in the red box (added for illustration) will remove the header image.
Another option would be to remove or change your site's "meta image," which is controlled in Websites > Site Settings > Logo. This is the image that renders as the header image by default.
Complete and current information on how to use NationBuilder is available in the documentation section.