docu for new options in site control panel

 plone/Products.CMFPlone#1734

adapt-and-extend/config/intro.rst

@@ -44,7 +44,7 @@ Mail
 Navigation
     Configure :doc:`how navigation is constructed <navigation>`. Which content types should appear in navigation, should folders on the top level become tabs, and which workflows to show.
 Site
-    Various :doc:`site wide settings <site>`: Site name, logo, metadata, settings for search engines and more.
+    Various :doc:`site wide settings <site>`: Site name, logo, metadata, default settings for handling of icons and preview images, settings for search engines and more.
 Add-ons
     :doc:`Activate and deactivate <add-ons>` add-ons that enhance Plone's functionality.
 Search

adapt-and-extend/config/site.rst

@@ -35,7 +35,29 @@ JavaScript for web statistics support
 Display publication date
     Show the date a content item was published in the byline.
 Icon visibility
-    Controls whether to show different icons for different types of content. Can be useful for content editors, but distracting for anonymous visitors. You can set it to show only for logged-in users.
+    Master control for enabling content type icons (Different icons for different types of content). Content type icons can be useful for content editors, but distracting for anonymous visitors.
+    You can set it to show only for logged-in users, all users or none at all. If this option is set to none or logged-in users only it will override all other settings  in portlets or content item settings.
+Thumb visibility
+    Master control for enabling preview images (aka thumbs) in list views, tables views  or portlets.
+    You can set it to show only for logged-in users, all users or none at all. If this option is set to none or logged-in users only it will override all related settings below as well those in individual portlet- or content item settings.
+
+
+No Thumbs in portlets
+   Suppress thumbs (preview images) in all portlets; this default can be overridden individually in selected portlets
+No thumbs in list views
+   Suppress thumbs in all list views; this default can be overriden individually
+No thumbs in summary views
+   Suppress thumbs in all summary views; this default can be overriden individually
+No thumbs in table views
+   Suppress thumbs in all tableviews and in folder contents view; this default can be overriden individually
+Thumb size for portlets
+   this default can be overriden individually
+Thumb size for listings
+   e.g. standard view; this default can be overriden individually
+Thumb size for tables
+   e.g., tabular view, folder content listing; this default can be overriden individually
+Thumb size for summary view
+   this default can be overriden individually
 Toolbar position
     On modern wide-screen monitors, having the Toolbar to the side provides most usable space. But some people prefer it to be on the top of their screen.
 Site based relative URL for toolbar Logo