Discovery API supports specifying a tile in a URL.

chrome/browser/resources/ntp4/suggestions_page.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 cr.define('ntp', function() {
   'use strict';
 
   var TilePage = ntp.TilePage;
 
   /**
@@ skipping 91 matching lines @@
       var title = this.querySelector('.title');
       title.textContent = data.title;
       title.dir = data.direction;
 
       var score = this.querySelector('.score');
       score.textContent = data.score;
 
       // Sets the tooltip.
       this.title = data.title;
 
-      var thumbnailUrl = 'chrome://thumb/' + data.url;
+      var thumbnailUrl;
+      if (data.urlImage) {

[Evan Stade, 2012/07/26 04:26:02]

use ternary operator

[beaudoin, 2012/07/26 17:08:37]

Done.

+        thumbnailUrl = data.urlImage;
+      } else {
+        thumbnailUrl = 'chrome://thumb/' + data.url;
+      }
       this.querySelector('.thumbnail').style.backgroundImage =
           url(thumbnailUrl);
 
       this.href = data.url;
 
       this.classList.remove('filler');
     },
 
     /**
      * Sets the color of the favicon dominant color bar.
@@ skipping 339 matching lines @@
     return oldData;
   }
 
   return {
     SuggestionsPage: SuggestionsPage,
     refreshData: refreshData,
   };
 });
 
 document.addEventListener('ntpLoaded', ntp.SuggestionsPage.onLoaded);