I use it coz it's free, everybody loves free progs
A zip file is include ICO, PNG & TIFF files!
ICO and PNG files have sizes: 256x356, 96x96, 48x48, 32x32, 24x24 & 16x16 px.
!!!TIFF file can be scaled to any size, because it contains all elements in the vector path!!!
Done with PhotoshopCS3