PNG Weather Icons

I was just wondering if Yahoo has any plans to change the icons used to display weather. I developed an intranet application that has a dark background and uses RSS to import the weather forecast on our homepage. Becasue of the dark background, the icons dont come out as good as intended since the GIF images used by Yahoo has a white matte.

Any ideas on how to get around this or does Yahoo have any plans to start using PNG images (without the Matte) in the immediate future? One that would blend seamlessly with any background?

Thanks.