Yes
gratus is right, they are
.DDS files.
Which some can be found in your
*\Conquer 2.0\data\MapItemIcon folder and the rest would be found in the extracted
data.wdf file. After extracting look in the
*\data\mapitemicon folder.
As
gratus stated goto linklist stickied above
(link in my siggy) and look for a how to on editing
.DDS files. Also if you don't want to extract the files yourself look in the
section you'll find extracted
.wdf file thread stickied there.