Add height and width for images

Author: mattcone

hacks.md

@@ -319,4 +319,4 @@ YouTube automatically generates an image for every video (`https://img.youtube.c
 
 The rendered output looks like this:
 
-<a href="https://www.youtube.com/watch?v=PYCxct2e0zI" rel="nofollow"><img src="https://img.youtube.com/vi/PYCxct2e0zI/0.jpg" alt="Less Than Jake — Scott Farcas Takes It On The Chin"></a>
+<a href="https://www.youtube.com/watch?v=PYCxct2e0zI" rel="nofollow"><img src="https://img.youtube.com/vi/PYCxct2e0zI/0.jpg" width="480" height="360" alt="Less Than Jake — Scott Farcas Takes It On The Chin"></a>

index.html

@@ -10,7 +10,7 @@
     <!-- Main jumbotron for a primary marketing message or call to action -->
     <div class="jumbotron">
       <div class="container">
-        <img src="/assets/images/markdown-mark-white.svg" alt="Markdown logo">
+        <img src="/assets/images/markdown-mark-white.svg" height="128" width="208" alt="Markdown logo">
         <p><i>The Markdown Guide</i> is a free and open-source reference guide that explains how to use Markdown, the simple and easy-to-use markup language you can use to format virtually any document.</p>
         <p><a class="btn btn-outline-inverse btn-lg" href="/getting-started/" role="button">Get Started</a></p>
       </div>