diff --git a/.env.docker b/.env.docker
index 5f5152968..e7f259f2e 100644
--- a/.env.docker
+++ b/.env.docker
@@ -378,7 +378,7 @@ MAIL_FROM_NAME="Pixelfed @ ${APP_DOMAIN}"
 
 # Defaults to "phpredis".
 #
-# See: https://docs.pixelfed.org/technical-documentation/config/#db_username
+# See: https://docs.pixelfed.org/technical-documentation/config/#redis_client
 #REDIS_CLIENT="phpredis"
 
 # Defaults to "tcp".
diff --git a/Dockerfile b/Dockerfile
index 3d12aba26..53037cb05 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -40,7 +40,7 @@ ARG RUNTIME_GID=33 # often called 'www-data'
 ARG APT_PACKAGES_EXTRA=
 
 # Extensions installed via [pecl install]
-ARG PHP_PECL_EXTENSIONS=
+ARG PHP_PECL_EXTENSIONS="redis imagick"
 ARG PHP_PECL_EXTENSIONS_EXTRA=
 
 # Extensions installed via [docker-php-ext-install]