diff --git a/source/localizable/feedspec/index.el.html.md.erb b/source/localizable/feedspec/index.el.html.md.erb
index 4160a80d..bfbc3fe9 100644
--- a/source/localizable/feedspec/index.el.html.md.erb
+++ b/source/localizable/feedspec/index.el.html.md.erb
@@ -317,6 +317,8 @@ thumbnail.
 > Τα links πρέπει να δημοσίως προσβάσιμα, ανεξάρτητα του domain στο οποίο
   φιλοξενούνται.
 
+> Το format AVIF δεν υποστηρίζεται.
+
 ##### Παράδειγμα
 
 ~~~ xml
diff --git a/source/localizable/feedspec/index.en.html.md.erb b/source/localizable/feedspec/index.en.html.md.erb
index 9dcb6a28..06f856a9 100644
--- a/source/localizable/feedspec/index.en.html.md.erb
+++ b/source/localizable/feedspec/index.en.html.md.erb
@@ -290,6 +290,8 @@ the image will be updated normally.
 > Images should not have bezels. The object shown in the image must have at
   least one dimension larger than 1000 pixels.
 
+> The AVIF format is not supported.
+
 ##### Example
 
 ~~~ xml