Add open graph image

index.html

 ---
-title: Feather
-description: Feather is a collection of simply beautiful open source icons. Each icon is designed on a 24x24 grid with an emphasis on consistency and simplicity.
+title: Feather – Simply beautiful open source icons
+description: Designed on a 24x24 grid with an emphasis on functionality, consistency and simplicity.
 links:
 - title: Donate
   url: https://www.paypal.com/cgi-bin/webscr?cmd=_donations&business=G6CPFZ6PQRZW8&lc=US&item_name=Feather&currency_code=USD&bn=PP%2dDonationsBF%3abtn_donateCC_LG%2egif%3aNonHosted
@@ -23,7 +23,9 @@ links:
   <meta name="description" content="{{ page.description }}">
   <meta property="og:title" content="{{ page.title }}">
   <meta property="og:description" content="{{ page.description }}">
-  <meta name="twitter:card" content="summary">
+  <meta property="og:image" content="assets/feather-preview.png">
+  <meta name="twitter:card" content="summary_large_image">
+  <meta name="twitter:site" content="@colebemis">
 
   <link rel="shortcut icon" type="image/png" href="assets/favicon.png">