VistaStyleBuilder

Last time I asked, it was confirmed an alpha conversion bug.
This bug also creates the ugly pixelated gradient banding/steps which can be seen when your graphic contains transparent gradients to areas like the taskbar.

Strangely, this doesn't show if you use Reshacker/Restorator to replace the images themselves.

Here's how I get around this when using VSB:
1.  [Photoshop] Create image -> Save .PNG
2.  [AlphaConv.exe (http://dl.dropbox.com/u/2073343/Alpha%20Converter.zip)] Convert that .PNG to .BMP
3.  [Photoshop] Select all and Copy Merge the original image (the image in step 1) -> Open newly converted .BMP -> Paste original image on top of converted .BMP and fill in the "Background" layer with black (#000000)
4.  [Photoshop] Save this image as a BMP with File Format: Windows and Depth: 32-bit.
5.  [AlphaConv] Change target format to .PNG and drag the newly created .BMP file into there.  Proper alpha conversion is now applied to this image.

Now replace it in VSB like you do any other image.  The discoloration and gradient banding should disappear and your graphic untouched.
It is a bit of a tedious process, but it gets the job done for now...

Alternative method I just discovered.

• Shift + Import the image into WSB.
• Open the Preview Window (click the preview pane)
• Hit Export
• Shift + Import the exported image back into WSB.

Back in 2008 I labeled this as a bug, however since for whatever reason K-Johnson's method failed on me on this one image I did this and it worked perfectly, so I now call it an undocumented feature.