Standard Windows Icon Size for ICO format
256 x 256 pixels – 32bit (24bit colour, 8bit transparency)
48 x 48 pixels – 32bit (24bit colour, 8bit transparency)
32 x 32 pixels – 32bit (24bit colour, 8bit transparency)
16 x 16 pixels – 32bit (24bit colour, 8bit transparency)
The actual sizes displayed at each of the headings are as follows:
Extra Large Icons – 256 x 256 pixels
Large Icons – 96 x 96 pixels (Automatically rendered by Windows from 256 version)
Medium Icons – 48 x 48 pixels
Small Icons – 16 x 16 pixels
List – 16 x 16 pixels
Details – 16 x 16 pixels
Tiles – 48 x 48 pixels
Content – 32 x 32 pixels