You need to use the skins in a battle, press Print Screen, exit the game, go to Program Files\Activision\Rome Total War\tgas and find the most recent file. Convert it to a jpg using IrfanView (search on google for it) or another image editor if you have one. Then, upload it onto www.imageshack.us and copy and paste the "Hotlink for Forums" into your post.

Hope that helped.