How do I use different program icons for different screen resolutions

I have created two different program icons.  One for 16 colors and the
other for 256 colors.  How do I "tell" my program which one to use
depending on the color pallete.  Also, how do I "insert" the two icons
into my program so they can be used.  Any suggestions would be greatly
appreciated.

Thanks in advance,

...Wade...