diff --git a/matrix/database_vacuum_instructions.md b/matrix/database_vacuum_instructions.md
new file mode 100644
index 0000000..26fc683
--- /dev/null
+++ b/matrix/database_vacuum_instructions.md
@@ -0,0 +1,5 @@
+1. Activate `synapse-admin` following instructions provided by playbook
+2. Use `synapse-admin` to clean rooms or what you don't need
+3. Stop `synapse`
+3. Run `REINDEX (VERBOSE) DATABASE dbnamehere;` from your db client
+4. Run `VACUUM FULL VERBOSE;` from your db client
diff --git a/nextcloud/var/www/html/nextcloud/config/config.s3.php b/nextcloud/var/www/html/nextcloud/config/config.s3.php
index 6273db2..369b99d 100644
--- a/nextcloud/var/www/html/nextcloud/config/config.s3.php
+++ b/nextcloud/var/www/html/nextcloud/config/config.s3.php
@@ -61,5 +61,23 @@ $CONFIG = array (
   'mail_smtppassword' => '',
   'maintenance' => false,
   'default_phone_region' => 'IT',
-	'preview_max_memory' => 768,
+	'enable_previews' => true,
+  'preview_max_x' => 4096,
+  'preview_max_y' => 4096,
+  'preview_max_memory' => 768,
+  'preview_max_filesize_image' => 50,
+  'enabledPreviewProviders' => [
+    'OC\Preview\PNG',
+    'OC\Preview\JPEG',
+    'OC\Preview\GIF',
+    'OC\Preview\HEIC',
+    'OC\Preview\BMP',
+    'OC\Preview\XBitmap',
+    'OC\Preview\MP3',
+    'OC\Preview\TXT',
+    'OC\Preview\MarkDown',
+    'OC\Preview\OpenDocument',
+    'OC\Preview\Krita',
+    'OC\Preview\PDF',
+  ],
 );