diff --git a/lib/Controller/AlbumsController.php b/lib/Controller/AlbumsController.php
index 0a8b5c2b..6d0855b7 100644
--- a/lib/Controller/AlbumsController.php
+++ b/lib/Controller/AlbumsController.php
@@ -75,7 +75,7 @@ class AlbumsController extends GenericClusterController
         return array_values($list);
     }
 
-    protected function getFileIds(string $name, ?int $limit = null): array
+    protected function getFiles(string $name, ?int $limit = null): array
     {
         // Get album
         $album = $this->timelineQuery->getAlbumIfAllowed($this->getUID(), $name);
@@ -84,8 +84,7 @@ class AlbumsController extends GenericClusterController
         }
 
         // Get files
-        $list = $this->timelineQuery->getAlbumFiles((int) $album['album_id'], $limit) ?? [];
-
-        return array_map(fn ($item) => (int) $item['fileid'], $list);
+        $id = (int) $album['album_id'];
+        return $this->timelineQuery->getAlbumFiles($id, $limit) ?? [];
     }
 }
diff --git a/lib/Controller/GenericClusterController.php b/lib/Controller/GenericClusterController.php
index 78976908..a0644310 100644
--- a/lib/Controller/GenericClusterController.php
+++ b/lib/Controller/GenericClusterController.php
@@ -69,18 +69,18 @@ abstract class GenericClusterController extends GenericApiController
             $this->init();
 
             // Get list of some files in this cluster
-            $fileIds = $this->getFileIds($name, 8);
+            $files = $this->getFiles($name, 8);
 
             // If no files found then return 404
-            if (0 === \count($fileIds)) {
+            if (0 === \count($files)) {
                 return new JSONResponse([], Http::STATUS_NOT_FOUND);
             }
 
-            // Shuffle the list so we don't always get the same preview
-            shuffle($fileIds);
+            // Put the files in the correct order
+            $this->sortFilesForPreview($files);
 
             // Get preview from image list
-            return $this->getPreviewFromImageList($fileIds);
+            return $this->getPreviewFromImageList($this->getFileIds($files));
         } catch (HttpResponseException $e) {
             return $e->response;
         } catch (\Exception $e) {
@@ -101,7 +101,7 @@ abstract class GenericClusterController extends GenericApiController
             $this->init();
 
             // Get list of all files in this cluster
-            $fileIds = $this->getFileIds($name);
+            $fileIds = $this->getFileIds($this->getFiles($name));
 
             // Get download handle
             $filename = $this->clusterName($name);
@@ -132,14 +132,13 @@ abstract class GenericClusterController extends GenericApiController
     abstract protected function getClusters(): array;
 
     /**
-     * Get a list of fileids for the given cluster for preview generation.
+     * Get a list of files with extra parameters for the given cluster
+     * Used for preview generation and download.
      *
      * @param string $name  Identifier for the cluster
      * @param int    $limit Maximum number of fileids to return
-     *
-     * @return int[]
      */
-    abstract protected function getFileIds(string $name, ?int $limit = null): array;
+    abstract protected function getFiles(string $name, ?int $limit = null): array;
 
     /**
      * Initialize and check if the app is enabled.
@@ -180,4 +179,29 @@ abstract class GenericClusterController extends GenericApiController
     {
         return $name;
     }
+
+    /**
+     * Put the file objects in priority list.
+     * Works on the array in place.
+     */
+    protected function sortFilesForPreview(array &$files)
+    {
+        shuffle($files);
+    }
+
+    /**
+     * Get the file ID for a file object.
+     */
+    protected function getFileId(array $file): int
+    {
+        return (int) $file['fileid'];
+    }
+
+    /**
+     * Get array of fileIds from array of file objects.
+     */
+    private function getFileIds(array $files): array
+    {
+        return array_map([$this, 'getFileId'], $files);
+    }
 }
diff --git a/lib/Controller/PlacesController.php b/lib/Controller/PlacesController.php
index 6856649f..f48393a6 100644
--- a/lib/Controller/PlacesController.php
+++ b/lib/Controller/PlacesController.php
@@ -40,10 +40,8 @@ class PlacesController extends GenericClusterController
         return $this->timelineQuery->getPlaces($this->root);
     }
 
-    protected function getFileIds(string $name, ?int $limit = null): array
+    protected function getFiles(string $name, ?int $limit = null): array
     {
-        $list = $this->timelineQuery->getPlaceFiles((int) $name, $this->root, $limit) ?? [];
-
-        return array_map(fn ($item) => (int) $item['fileid'], $list);
+        return $this->timelineQuery->getPlaceFiles((int) $name, $this->root, $limit) ?? [];
     }
 }
diff --git a/lib/Controller/TagsController.php b/lib/Controller/TagsController.php
index 1a8e9aac..e553bebf 100644
--- a/lib/Controller/TagsController.php
+++ b/lib/Controller/TagsController.php
@@ -77,10 +77,8 @@ class TagsController extends GenericClusterController
         return $this->timelineQuery->getTags($this->root);
     }
 
-    protected function getFileIds(string $name, ?int $limit = null): array
+    protected function getFiles(string $name, ?int $limit = null): array
     {
-        $list = $this->timelineQuery->getTagFiles($name, $this->root, $limit) ?? [];
-
-        return array_map(fn ($item) => (int) $item['fileid'], $list);
+        return $this->timelineQuery->getTagFiles($name, $this->root, $limit) ?? [];
     }
 }