diff --git a/config/config.sample.php b/config/config.sample.php
index 72834009201931033319d1e8e69b78ed5346bc00..db6eaf852af514d394245fa78f84acbcbf213243 100644
--- a/config/config.sample.php
+++ b/config/config.sample.php
@@ -183,4 +183,12 @@ $CONFIG = array(
 'customclient_desktop' => '', //http://owncloud.org/sync-clients/
 'customclient_android' => '', //https://play.google.com/store/apps/details?id=com.owncloud.android
 'customclient_ios' => '' //https://itunes.apple.com/us/app/owncloud/id543672169?mt=8
+
+// PREVIEW
+/* the max width of a generated preview, if value is null, there is no limit */
+'preview_max_x' => null,
+/* the max height of a generated preview, if value is null, there is no limit */
+'preview_max_y' => null,
+/* the max factor to scale a preview, default is set to 10 */
+'preview_max_scale_factor' => 10,
 );