As of OSX specifications, the pixel standard that can be used are 16 × 16, 32 × 32, 48 × 48, 128 × 128, 256 × 256, 512 × 512, and 1024 × 1024 pixels, with both 1- and 8-bitalpha channels and multiple image states (example: open and closed folders). The fixed-size icons can be scaled by the operating system and displayed at any intermediate size. So how to get the high quality icon from an application on Mac?