XnView is a picture browser. You will need to have a EDITOR in order to manipulate the psd file.
Thanks, Stefek for the files!
I know, XnView is just a browser - but I was able to extract the frame I needed and edit it with PaintShopPro

.
So, attached three pictures:
1. a transparent-background PNG of your chef-hat (I get a black background when I open the pic here

).
2. the old powered.jpg
3. my newly created powered.png with transparent background.
Since transparent .pngs are supported by all up-to-date browsers (Firefox 3, Opera 9.5+ and Internet Explorer 7+), I think it is safe to use them.
The WB-team may feel free to include the picture in upcoming WB-releases as a substitute for the powered.jpg. Since with a transparent background it would fit with all templates.
I hope you like it, tried to make it look as close to the original as possible.
Have a nice day!
Best regards,
VSG
PS: Don't get confused that the new pic is shown a bit blurred below - seems to be an attachment-preview issue. It is clear as you can see
here on my website.