diff --git a/TODO b/TODO
index f8a36caa..af9e314e 100644
--- a/TODO
+++ b/TODO
@@ -1,3 +1,5 @@
+- vipstumbnail is broken for the gamma trick png on eric brasseur's page
+
 - vipsthumbnail could shrink-on-load openslide and pyr tiff as well?
 
 - look again at gcc auto-vectorisation, what would we need to do to use this?