Why base64Encode images in CSS?

Possible duplicate:
embedding background image data in css as base64, good or bad practice

I just looked at the source on my Google Chrome homepage and noticed that the images are base64 encoded in CSS. What is the advantage of this? I am tempted to think that this is just to shorten HTTP requests, but since it is a local application, it does not matter, anyway? Can it just upload the image locally?

menu > [checked]:before {
  content: url("data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAkAAAAJCAYAAADgkQYQAAAARklEQVQYlWNgwA+MgViQkIJ3QKzEAFVpjEPBf5giJaiAMRYF72DWKSEJlKMpgNsgiCTxH5sCbG7AqgBZ4V2sCv7//08QAwAUfjKKBs+BFgAAAABJRU5ErkJggg==");
  display: inline-block;
  height: 9px;
  margin: 0 5px;
  vertical-align: 50%;
  width: 9px;
}