diff --git a/app/AlbumSources/BackblazeB2Source.php b/app/AlbumSources/BackblazeB2Source.php
index b7e3986..c9a4c9e 100644
--- a/app/AlbumSources/BackblazeB2Source.php
+++ b/app/AlbumSources/BackblazeB2Source.php
@@ -102,30 +102,39 @@ class BackblazeB2Source extends AlbumSourceBase implements IAlbumSource
     public function getUrlToPhoto(Photo $photo, $thumbnail = null)
     {
         $client = $this->getClient();
-        $storagePathToFile = $this->getPathToPhoto($photo, $thumbnail);
-
-        /*
-         * From https://www.backblaze.com/b2/docs/b2_download_file_by_name.html:
-         * The base URL to use comes from the b2_authorize_account call, and looks something like
-         * https://f345.backblazeb2.com. The "f" in the URL stands for "file", and the number is the cluster
-         * number containing your account. To this base, you add "file/", your bucket name, a "/", and then the
-         * name of the file. The file name may itself include more "/" characters.
-         */
-        $fileDownloadUrl = sprintf('%s/file/%s/%s', $client->getDownloadUrl(), $this->configuration->container_name, $storagePathToFile);
+        $pathOnStorage = $this->getPathToPhoto($photo, $thumbnail);
 
         switch ($this->bucketType)
         {
             case self::BUCKET_TYPE_PRIVATE:
-                // TODO: use the B2 b2_download_file_by_id method so filenames are harder to guess
                 if (is_null($this->downloadToken))
                 {
                     $this->downloadToken = $client->getDownloadAuthToken();
                 }
 
-                return sprintf('%s?Authorization=%s', $fileDownloadUrl, $this->downloadToken);
+                // Once I sort out the issue with b2_download_file_by_id, this line can be removed
+                return sprintf('%s/file/%s/%s?Authorization=%s', $client->getDownloadUrl(), $this->configuration->container_name, $pathOnStorage, $this->downloadToken);
+
+                /** @var BackblazeB2FileIdCache $b2Cache */
+                $b2Cache = BackblazeB2FileIdCache::where('storage_path', $pathOnStorage)->first();
+                if (is_null($b2Cache))
+                {
+                    // TODO: lookup the file on B2 to get the file ID
+                    Log::warning(sprintf('B2 file ID not found in cache: %s', $pathOnStorage));
+                    return '';
+                }
+
+                return sprintf('%s/b2api/v2/b2_download_file_by_id?fileId=%s&Authorization=%s', $client->getDownloadUrl(), urlencode($b2Cache->b2_file_id), urlencode($this->downloadToken));
 
             case self::BUCKET_TYPE_PUBLIC:
-                return $fileDownloadUrl;
+                /*
+                 * From https://www.backblaze.com/b2/docs/b2_download_file_by_name.html:
+                 * The base URL to use comes from the b2_authorize_account call, and looks something like
+                 * https://f345.backblazeb2.com. The "f" in the URL stands for "file", and the number is the cluster
+                 * number containing your account. To this base, you add "file/", your bucket name, a "/", and then the
+                 * name of the file. The file name may itself include more "/" characters.
+                 */
+                return sprintf('%s/file/%s/%s', $client->getDownloadUrl(), $this->configuration->container_name, $pathOnStorage);
         }
     }