diff --git a/config/locales/server.en.yml b/config/locales/server.en.yml
index 5706ad201..18e75e4ae 100644
--- a/config/locales/server.en.yml
+++ b/config/locales/server.en.yml
@@ -669,7 +669,7 @@ en:
     username_change_period: "The number of days after registration that accounts can change their username."
 
     allow_uploaded_avatars: "Allow users to upload their custom avatars"
-    allow_animated_avatars: "Allow users to use animated gif for avatars"
+    allow_animated_avatars: "Allow users to use animated gif for avatars. WARNING: it is highly recommended to run the avatars:regenerate rake task after changing that setting."
     default_digest_email_frequency: "How often users receive digest emails by default. They can change this setting in their preferences."
 
   notification_types:
diff --git a/lib/tasks/avatars.rake b/lib/tasks/avatars.rake
new file mode 100644
index 000000000..037b766a8
--- /dev/null
+++ b/lib/tasks/avatars.rake
@@ -0,0 +1,13 @@
+desc "re-generate avatars"
+task "avatars:regenerate" => :environment do
+  RailsMultisite::ConnectionManagement.each_connection do |db|
+    puts "Generating avatars for: #{db}"
+
+    User.select(:uploaded_avatar_id).where("uploaded_avatar_id IS NOT NULL").all.each do |u|
+      Jobs.enqueue(:generate_avatars, upload_id: u.uploaded_avatar_id)
+      putc "."
+    end
+
+  end
+  puts "\ndone."
+end