adjust link preview

app/views/shared/_meta.html.erb

@@ -9,7 +9,10 @@
 <meta property="og:type" content="website">
 <meta property="og:url" content="<%= root_url %>">
 <meta property="og:site_name" content="DocuSeal">
-<% unless content_for(:disable_image_preview) %>
+<% if content_for(:disable_image_preview) %>
+  <meta property="og:image" content="">
+  <meta name="twitter:image" content="">
+<% else %>
   <meta property="og:image" content="<%= image_pack_url('images/preview.png') %>">
   <meta property="og:image:width" content="800">
   <meta property="og:image:height" content="800">