There are differences in the use of picture id's from one HPS game to another. In one game the designer used a picture for one side that was used for the other in another game. In addition within the games wagons and guns used the same picture for both sides. The only way around this if you want to create side specific pictures is to create a new units.bmp for each game after studying the OOB's to determine which side uses which picturein that particulr game. There is no one set that will work with all the games. If you're looking for some color picture units.bmp you can try my site at
http://home.comcast.net/~krmiller_cor/
Gen. Ken Miller
Army of the Shenandoah