<ul class="phones">
    <li ng-repeat="phone in phones" class="thumbnail">
        <img ng-src="{{phone.imageUrl}}">
    </li>
</ul>

他们要求：

Replace the ng-src directive with a plain old src attribute.
Using tools such as Firebug,or Chrome’s Web Inspector,or inspecting the
webserver access logs,confirm that the app is indeed making an
extraneous request to /app/%7B%7Bphone.imageUrl%7D%7D (or
/app/{{phone.imageUrl}}).

我这样做，它给了我正确的结果：

<li class="thumbnail ng-scope" ng-repeat="phone in phones">
    <img src="img/phones/motorola-xoom.0.jpg">
</li>

有什么原因吗？