The new Windows Vista looks cool. Vista's "aero glass" see-through window frames and green liquid-like progress bars resemble effects that Mac users have enjoyed for years. To support this look-and-feel and to comply with computer technology that will be delivered over the next decade, Windows Vista introduces a new icon format..
Windows Vista supports high-resolution icons that are 256 x 256 pixels. Vista icons are stored in the PNG format. With PNG compression, the size of an icon is reduced and because PNG is loss-less and supports 8bit alpha channel, the quality of icon remains unchanged, despite compression.