[rorrr]

HTML doesn't support vector images well. Yeah, you have SVG in modern browsers, but which one is easier?

    <img src="logo.png">

or

    <embed src="http://upload.wikimedia.org/wikipedia/en/4/4a/Commons-logo.svg" type="image/svg+xml" />

    (fails in IE8- and IE9 quirks)

[paulirish]

You can do <img src="logo.svg"> in IE9 and every other browser. In fact, you can do an inline <svg> image inside of your HTML in all those browsers as well. The <embed> is long gone.

[alexpenny]

CSS does support vector images. It's equally easy to do as their raster pals.