SVGMagic is a simple jQuery plugin that searchs for SVG images (including background-images) on your website andcreates PNG versions if the browser doesn’t support SVG.
Wondering why you should use SVG images? SVG images are vector based! Meaning that they will be as sharp as hell no matter how big they are. In other words: one file for every size. See it yourself: (assuming you are now using a browser that understands SVG images)