Hier noch der entpsrechende Text aus der MS-Seite:
MS nutzt nicht nur eigene Tools ;)
Photoshop is the recommended image creation tool
because Gif Movie Gear, the tool we use to create the .ico files, offers a direct import of Photoshop files. Any image created in Photoshop that uses the "
RGB" mode has an alpha channel attached. If there is transparency in the image or layer, that channel becomes meaningful for icon purposes.
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