<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="170" height="200">
  <defs>
    <filter id="filter">
      <feGaussianBlur stdDeviation="5" />
    </filter>
    <mask id="mask">
      <ellipse cx="50%" cy="50%" rx="25%" ry="25%" fill="white" filter="url(#filter)"></ellipse>
    </mask>
  </defs>

  <image xlink:href="https://s3-us-west-2.amazonaws.com/s.cdpn.io/3/Harry-Potter-1-.jpg" width="170" height="200" mask="url(#mask)"></image>
</svg>