title: "Duplicate Resources" error when building Android app
body: <p>When I build my Android app, I get this error:</p>
  <pre class="lang-none prettyprint-override"><code>Error:Error: Duplicate resources: E:\Android\LED\app\src\main\res\drawable-hdpi\login_bg.png:drawable-hdpi-v4/login_bg, E:\Android\LED\app\src\main\res\drawable-hdpi\login_bg.9.png:drawable-hdpi-v4/login_bg
  Error:Execution failed for task ':app:mergeDebugResources'.
  &gt; E:\Android\LED\app\src\main\res\drawable-hdpi\login_bg.png: Error: Duplicate resources: E:\Android\LED\app\src\main\res\drawable-hdpi\login_bg.png:drawable-hdpi-v4/login_bg, E:\Android\LED\app\src\main\res\drawable-hdpi\login_bg.9.png:drawable-hdpi-v4/login_bg
  </code></pre>
  <p>I am not able to properly understand the error. What file is duplicated here? What am I supposed to do to rectify it?</p>