photos.kameronkenny.com/_includes/svg_shadow.html

<svg class="shadow">
  <defs>
    <filter id="shadow">
      <feOffset result="offOut" in="SourceAlpha" dy="2" />
      <feBlend in="SourceGraphic" in2="offOut" mode="normal" />
    </filter>
  </defs>
</svg>