title: android drawable image takes lot of memory compared to its disk size
body: <p>I have following drawable with different sizes for mdpi, hdpi, xhdpi....</p>
  
  <pre><code>-rw-r--r--@ 1 xxx  yyy    31K Apr 16 14:19 myImage.9.png
  -rw-r--r--@ 1 xxx  yyy    63K Apr 16 14:19 myImage.9.png
  -rw-r--r--@ 1 xxx  yyy    95K Apr 16 14:19 myImage.9.png
  -rw-r--r--@ 1 xxx  yyy   196K Apr 16 14:19 myImage.9.png
  -rw-r--r--@ 1 xxx  yyy   307K Apr 16 14:19 myImage.9.png
  </code></pre>
  
  <p>I use it as follows</p>
  
  <pre><code>    &lt;ImageView
          android:paddingLeft="10dp"
          android:paddingRight="0dp"
          android:layout_centerVertical="true"
          android:layout_width="25dp"
          android:layout_height="25dp"
          android:scaleType="fitCenter"
          android:src="@drawable/myImage" /&gt;
  </code></pre>
  
  <p>My app at this point takes 20MB</p>
  
  <p>If I make a change <code>android:src="@null"</code></p>
  
  <p>My app at this point takes 10MB</p>
  
  <p>Why does the drawable takes so much memory where actual size is lot less??</p>