Discovery API supports specifying a tile in a URL.

chrome/browser/extensions/api/discovery/discovery_api.cc

 // 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.
 
 #include "chrome/browser/extensions/api/discovery/discovery_api.h"
 
 #include "base/values.h"
 #include "chrome/browser/extensions/api/discovery/suggested_link.h"
 #include "chrome/browser/extensions/api/discovery/suggested_links_registry.h"
 #include "chrome/browser/extensions/api/discovery/suggested_links_registry_factory.h"
@@ skipping 16 matching lines @@
 
   double score = 1.0;
   if (params->details.score != NULL) {
     score = *params->details.score;
     if (score < 0.0 || score > 1.0) {
       error_ = kInvalidScore;
       return false;
     }
   }
 
+  std::string empty;
+  const std::string* url_image = &empty;
+  if (params->details.url_image != NULL)
+    url_image = params->details.url_image.get();
+
   extensions::SuggestedLinksRegistry* registry =
       extensions::SuggestedLinksRegistryFactory::GetForProfile(profile());
   scoped_ptr<extensions::SuggestedLink> suggested_link(
       new extensions::SuggestedLink(params->details.link_url,
-                                    params->details.link_text, score));
+                                    params->details.link_text,
+                                    *url_image,
+                                    score));
   registry->Add(extension_id(), suggested_link.Pass());
   return true;
 }
 
 bool DiscoveryRemoveSuggestionFunction::RunImpl() {
   scoped_ptr<discovery::RemoveSuggestion::Params> params(
       discovery::RemoveSuggestion::Params::Create(*args_));
   EXTENSION_FUNCTION_VALIDATE(params.get());
 
   extensions::SuggestedLinksRegistry* registry =
       extensions::SuggestedLinksRegistryFactory::GetForProfile(profile());
   registry->Remove(extension_id(), params->link_url);
 
   return true;
 }
 
 bool DiscoveryClearAllSuggestionsFunction::RunImpl() {
   extensions::SuggestedLinksRegistry* registry =
       extensions::SuggestedLinksRegistryFactory::GetForProfile(profile());
   registry->ClearAll(extension_id());
 
   return true;
 }
 
 }  // namespace extensions