Working with the Windows ICO format
ICO sizes and colors
IconPainter is currently programmed to deal with two ICO image sizes - 16 by 16 pixels and
32 by 32 pixels. These sizes are the most common and will provide an icon for almost any
situation. In addition IconPainter will allow icons to have up to the maximum of 256 colors.
Infact IconPainter always saves ICO images as though they had 256 colors even though they may
have just a few.
Coloring in ICO.
IconPainter always has a background color but when saving files in the ICO format this
background color is treated as the areas of the icon which are to be transparent. For this
reason edit an ICO image using a background color which does not appear in the icon's image.
(White is often a good choice for this). Also try and avoid using the antialiasing feature
in IconPainter with ICO images because this produces color gradients based on a given
background color and there's no saying what background color Windows might display the icon
over.