diff --git a/index.md b/index.md
index 36dd15b..3a1bdef 100644
--- a/index.md
+++ b/index.md
@@ -10,6 +10,7 @@ Manage Hetzner Cloud server instances
 * [Default Variables](#default-variables)
   * [hcloud_server](#hcloud-server)
   * [hcloud_server_default_api_token](#hcloud-server-default-api-token)
+  * [hcloud_server_default_image](#hcloud-server-default-image)
   * [hcloud_server_rdns](#hcloud-server-rdns)
   * [hcloud_server_volumes](#hcloud-server-volumes)
 * [Dependencies](#dependencies)
@@ -34,9 +35,9 @@ hcloud_server:
   type: cx11
   ssh_keys: []
   image:
-    location: "{{ hcloud_server_location }}"
-    datacenter: "{{ hcloud_server_datacenter }}"
-    api_token: "{{ hcloud_server_api_token | default(omit) }}"
+  location: "{{ hcloud_server_location }}"
+  datacenter: "{{ hcloud_server_datacenter }}"
+  api_token: "{{ hcloud_server_api_token | default(omit) }}"
 ```
 
 ### hcloud_server_default_api_token
@@ -47,6 +48,14 @@ hcloud_server:
 hcloud_server_default_api_token: _unset_
 ```
 
+### hcloud_server_default_image
+
+#### Default value
+
+```YAML
+hcloud_server_default_image: centos-7
+```
+
 ### hcloud_server_rdns
 
 #### Default value