tighterning checks on folder creation, a=chris

diff --git a/src/models/GroupModel.php b/src/models/GroupModel.php
index 6abcfe2fd..840833b1f 100644
--- a/src/models/GroupModel.php
+++ b/src/models/GroupModel.php
@@ -1596,7 +1596,8 @@ class GroupModel extends Model implements MediaConstants
                     $group_prefix_path = $resource_path."/$group_prefix";
                     $no_redirect_thumb_path = $thumb_path;
                     $thumb_path = "$group_prefix_path/t$group_hash";
-                    if (!file_exists($group_prefix_path)) {
+                    if (!file_exists($group_prefix_path) &&
+                        file_exists($group_path . $sub_path) && $create) {
                         L\makePath($group_prefix_path);
                     }
                     $redirected = true;
@@ -1605,6 +1606,8 @@ class GroupModel extends Model implements MediaConstants
             if (file_exists($group_path . $sub_path) &&
                 file_exists($thumb_path . $sub_path)) {
                 return [$group_path . $sub_path, $thumb_path . $sub_path];
+            } elseif (!$create) {
+                return false;
             }
         } elseif (!$create) {
             return false;
@@ -2161,7 +2164,7 @@ class GroupModel extends Model implements MediaConstants
         if (!move_uploaded_file($tmp_name, "$folder/$file_name")) {
             return;
         }
-        $this->makeThumbStripExif ($file_name, $folder, $thumb_folder,
+        $this->makeThumbStripExif($file_name, $folder, $thumb_folder,
             $mime_type);
         if (C\nsdefined('FFMPEG') && in_array($mime_type, [
             'video/mp4', 'video/webm', 'video/ogg', 'video/avi',
@@ -2203,7 +2206,7 @@ class GroupModel extends Model implements MediaConstants
         $sub_path = "")
     {
         $folders = $this->getGroupPageResourcesFolders($group_id, $page_id,
-            $sub_path, true);
+            $sub_path);
         if (!$folders) {
             return false;
         }
@@ -2418,6 +2421,9 @@ class GroupModel extends Model implements MediaConstants
         $resources = [];
         $time = time();
         foreach ($pre_resources as $pre_resource) {
+            if (!file_exists($pre_resource)) {
+                continue;
+            }
             $resource = [];
             $name = substr($pre_resource, $folder_len);
             $resource['name'] = $name;
@@ -2428,9 +2434,6 @@ class GroupModel extends Model implements MediaConstants
             $resource['is_compressed'] = false;
             $resource['is_writable'] = false;
             $resource['media_type'] = false;
-            if (!file_exists($pre_resource)) {
-                continue;
-            }
             if (is_dir($pre_resource)) {
                 $resource['is_dir'] = true;
             } else {