Edit in JSFiddle

var myApp = angular.module('myApp', []);

myApp.controller('myCtrl',
    function ($scope) {
        $scope.url = 'cdn1.www.st-hatena.com/users/ho/howdy39/profile.gif';
    }
);

<div ng-app="myApp">
    <div ng-controller="myCtrl">
        <img src="http://{{url}}"/>
        <img ng-src="http://{{url}}"/>
    </div>
</div>