Docs: Add figure captions to images

Bug: 18334770
Change-Id: I4ed95bb638b6502129d59c099de9a0cd8b16ccb4
diff --git a/src/devices/audio/index.jd b/src/devices/audio/index.jd
index dd3109b..c42bca7 100644
--- a/src/devices/audio/index.jd
+++ b/src/devices/audio/index.jd
@@ -2,7 +2,7 @@
 @jd:body
 
 <!--
-    Copyright 2013 The Android Open Source Project
+    Copyright 2014 The Android Open Source Project
 
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
@@ -26,8 +26,9 @@
   The following figure and list describe how audio functionality is implemented and the relevant
   source code that is involved in the implementation:
 </p>
-<p>
-  <img src="images/audio_hal.png" alt="Audio architecture" />
+  <img src="images/audio_hal.png" alt="Audio architecture" id="figure1" />
+<p class="img-caption">
+  <strong>Figure 1.</strong> Android audio architecture
 </p>
 <dl>
   <dt>