Earlier quoted context omitted.
it looks as if the colour is just a background-color attribute in CSS, which changes on mouseover. If so, it should be white->transparent anti-aliased in the RK image, which is looks like it's trying to be. Vector, e.g. drawn with Canvas, would be better (e.g. with a fallback to a single colour png.)
Why would you draw the vector manually with canvas when the browser can do it (SVG)?
Generating the relevant shapes and lines for a simple logo would be easy this way, although probably would require a larger download vs. a vector image, since the canvas method would need to load extra javascript to duplicate the SVG support built in to the browser.
I'm not saying it is necessarily a better idea, just that I've had more success with canvas drawing methods than trying to actually make a vector image.