On prod this needs to be `developer.cdn.mozilla.net/media/img/avatar.png` to serve from the CDN. Per django convention, we store the image/media hostname in [`settings.MEDIA_URL`](https://github.com/mozilla/kuma/blob/master/settings.py#L329) and then override it in `settings_local.py` for each environment.

[The `gravatar_url` default parameter](https://github.com/mozilla/kuma/blob/master/apps/devmo/models.py#L176-L177) is [`DEFAULT_AVATAR` which is already built from `settings.MEDIA_URL`](https://github.com/mozilla/kuma/blob/master/apps/devmo/models.py#L37-L38) So, the real fix for showing MDN avatars on your local box is to add this line to your `settings_local.py` file:
```
MEDIA_URL = 'https://developer.cdn.mozilla.net/media/'
```
![2014-04-15_2145](https://cloud.githubusercontent.com/assets/71928/2715588/2627dab2-c511-11e3-97e0-8243413aebba.png)