<!DOCTYPE html>
<html>
<head>
  <title>background-size: 100% 100%; stretch</title>
  <style type="text/css">
#outer
{
  border: 10px solid black;
  width: 60px;
  height: 120px;
}
#inner
{
  width: 60px;
  height: 120px;
  background-image: url(blue-8x20-green-16x20.png);
  background-repeat: no-repeat;
  background-size: 100% 100%;
}
#innermost
{
  width: 15px;
  height: 120px;

  /* obscure sampling artifacts at the color boundary */
  border-right: 10px solid black;
}
  </style>
</head>
<body>
<div id="outer"><div id="inner"><div id="innermost"></div></div></div>
</body>
</html>