Modify thumb folder name so closer to original resource folder name, a=chris

diff --git a/src/controllers/ResourceController.php b/src/controllers/ResourceController.php
index 2491d4904..c4dc6e47c 100644
--- a/src/controllers/ResourceController.php
+++ b/src/controllers/ResourceController.php
@@ -172,10 +172,11 @@ class ResourceController extends Controller implements CrawlConstants
             $group_model = $this->model('group');
             $group = $group_model->getGroupById($group_id, $user_id);
             if (!$group) { return false; }
-            $hash_word = (isset($_REQUEST['t'])) ? 'thumb' : 'group';
+            $prefix_word = (isset($_REQUEST['t'])) ? 't' : '';
             $subfolder = L\crawlHash(
-                $hash_word . $group_id. $page_id . C\AUTH_KEY);
+                'group' . $group_id. $page_id . C\AUTH_KEY);
             $prefix_folder = substr($subfolder, 0, 3);
+            $subfolder = $prefix_word . $subfolder;
             $add_to_path = true;
         }
         if ($add_to_path) {
diff --git a/src/models/GroupModel.php b/src/models/GroupModel.php
index 3839ce465..ee0e853ee 100644
--- a/src/models/GroupModel.php
+++ b/src/models/GroupModel.php
@@ -1202,15 +1202,16 @@ class GroupModel extends Model implements MediaConstants
         $sub_path = ($sub_path == "/" || $sub_path == "") ? "" : "/$sub_path";
         $group_page_folder = L\crawlHash(
             "group" . $group_id. $page_id . C\AUTH_KEY);
-        $thumb_page_folder = L\crawlHash(
+        $old_thumb_page_folder = L\crawlHash(
             "thumb" . $group_id. $page_id . C\AUTH_KEY);
         $group_prefix = substr($group_page_folder, 0, 3);
-        $thumb_prefix = substr($thumb_page_folder, 0, 3);
+        $old_thumb_prefix = substr($old_thumb_page_folder, 0, 3);
         $resource_path = C\APP_DIR . "/resources";
         $group_prefix_path = $resource_path."/$group_prefix";
-        $thumb_prefix_path = $resource_path."/$thumb_prefix";
+        $old_thumb_prefix_path = $resource_path."/$old_thumb_prefix";
         $group_path = "$group_prefix_path/$group_page_folder";
-        $thumb_path = "$thumb_prefix_path/$thumb_page_folder";
+        $thumb_path = "$group_prefix_path/t$group_page_folder";
+        $old_thumb_path = "$old_thumb_prefix_path/$old_thumb_page_folder";
         if (file_exists($group_path)) {
             if ($check_redirect &&
                 file_exists($group_path . "/$redirect_filename")) {
@@ -1235,6 +1236,9 @@ class GroupModel extends Model implements MediaConstants
                     $group_path = $tmp_path;
                 }
             }
+            if (file_exists($old_thumb_path) && !file_exists($thumb_path)) {
+                rename($old_thumb_path, $thumb_path);
+            }
             $full_group_path = $group_path . $sub_path;
             $full_thumb_path = $thumb_path . $sub_path;
             if ((file_exists($full_group_path) || L\makePath($full_group_path))