Add special-gallery back thumbnail and hide sort button for specials

viewer/image.py

@@ -141,10 +141,20 @@ def render_image(request, path_text, full_path, special=None):
     except Exception:
         dir_text = ""
 
-    # For special galleries hide the Back control but still present Home
+    # Back (directory) and Home (root) links and thumbnails
+    # For special galleries we still want to show a Back link that points
+    # to the special gallery root — populate `back_thumb` with the
+    # thumbnail of the first image in that special gallery so the UI can
+    # display a representative image. For non-special views keep the
+    # existing behavior (thumbnail for parent directory).
     if special is not None:
         back_url = None
-        back_thumb = None
+        # images_sorted is already the special list in the requested order
+        try:
+            first_image = images_sorted[0] if len(images_sorted) > 0 else None
+            back_thumb = thumb_for(first_image)
+        except Exception:
+            back_thumb = None
     else:
         back_url = gallery_url(
             Path(dir_text) if dir_text != "" else None, True, query_state