<!DOCTYPE html>
<svg width="100" height="200" style="background-color: red">
  <image width="100" height="200" preserveAspectRatio="none"
         xlink:href="data:image/svg+xml,<svg xmlns='http://www.w3.org/2000/svg' width='50%' height='50%' viewBox='0 0 100 100'><rect width='100' height='100' fill='green'/></svg>"/>
</svg>