IE8 + Retina e imagens responsivas

.logo {
  display: block;
  width: 100px;
  height: 80px;
  text-indent: -9999em;
  background: url(img/logo.png) no-repeat;
  background-size: cover;
  @media
    (-webkit-min-device-pixel-ratio: 2),
    (min-resolution: 192dpi) {
      background-image: url(img/logo@2x.png);
    }
  @media
    (max-width: 700px) {
      width: 75px;
      height: 60px;
    }
}