title: Calaculate top margin using SASS
body: <p>I need to calculate value for top margin dynamically from a div of fixed sized containing image. The image's height is variable.</p>
  
  <p>Here is the HTML:</p>
  
  <pre><code>&lt;div&gt;
   &lt;img src="path for image" /&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>And the CSS: </p>
  
  <pre><code>div {width:300px; height:300px;}
  img {margin-top: ??????}
  </code></pre>
  
  <p><code>margin-top</code> should be calculated by deducting the image's height from div's height..</p>
  
  <p>Is it possible by using SASS?</p>