Ember isn't loading some images in production

I have an Ember-cli 1.13 app that has a lot of images stored in the public directory. Now, it will correctly load all images except those in a particular component.

The component is called like this:

{{list-item url="list-url" name="List Name" price="240"}}

Internally, the component is this:

<a href="http://ift.tt/1QmY77j}}">
  <img src="/{{url}}.png" alt='Picture of the {{name}}' />
  <p class="item-name">{{name}}</p>
  ...
</a>

When I build the application and launch to heroku the broken path is

http://ift.tt/1Q2qFXY

Which is the same as the localhost path except with a different domain obviously.

All of the other images work when not used with components.

Where am I going wrong?