Icon color and Icon Size information is controlled by following entries in Registry. Navigate to HKEY_CURRENT_USER\Control Panel\Desktop\WindowMetrics and look for two keys by the following name:"Shell Icon BPP""Shell Icon Size" Value of "Shell Icon BPP" determines bits per pixel (color depth) and value of "Shell Icon Size" determines icon size in pixels. You can determine number of colors that Icon have by raising 2 to the power of "Shell Icon BPP" value. If value is 16, total number of colors (or color depth) is 2^16 = 65536