fix thumbnails docs

docs/_includes/components/thumbnails.html

@@ -46,7 +46,7 @@
     <div class="row">
       <div class="col-sm-6 col-md-4">
         <div class="thumbnail">
-          <img data-src="holder.js/300x200" alt="Generic placeholder thumbnail">
+          <img data-src="holder.js/100%x200" alt="Generic placeholder thumbnail">
           <div class="caption">
             <h3>Thumbnail label</h3>
             <p>Cras justo odio, dapibus ac facilisis in, egestas eget quam. Donec id elit non mi porta gravida at eget metus. Nullam id dolor id nibh ultricies vehicula ut id elit.</p>
@@ -56,7 +56,7 @@
       </div>
       <div class="col-sm-6 col-md-4">
         <div class="thumbnail">
-          <img data-src="holder.js/300x200" alt="Generic placeholder thumbnail">
+          <img data-src="holder.js/100%x200" alt="Generic placeholder thumbnail">
           <div class="caption">
             <h3>Thumbnail label</h3>
             <p>Cras justo odio, dapibus ac facilisis in, egestas eget quam. Donec id elit non mi porta gravida at eget metus. Nullam id dolor id nibh ultricies vehicula ut id elit.</p>
@@ -66,7 +66,7 @@
       </div>
       <div class="col-sm-6 col-md-4">
         <div class="thumbnail">
-          <img data-src="holder.js/300x200" alt="Generic placeholder thumbnail">
+          <img data-src="holder.js/100%x200" alt="Generic placeholder thumbnail">
           <div class="caption">
             <h3>Thumbnail label</h3>
             <p>Cras justo odio, dapibus ac facilisis in, egestas eget quam. Donec id elit non mi porta gravida at eget metus. Nullam id dolor id nibh ultricies vehicula ut id elit.</p>
@@ -80,7 +80,7 @@
 <div class="row">
   <div class="col-sm-6 col-md-4">
     <div class="thumbnail">
-      <img data-src="holder.js/300x200" alt="...">
+      <img data-src="holder.js/300x300" alt="...">
       <div class="caption">
         <h3>Thumbnail label</h3>
         <p>...</p>