For taking screenshots themselves I recommend the free program called Fraps, which you can get from www.fraps.com
I think you can only remove the HUD (without editing the picture that is, but I think editing pictures for this reason is okay - Brennus may correct me if I'm wrong) is to play with minimal UI. You can turn that on in the settings file in... I believe ...RTW\EB\settings. Can't check right now to be sure, but if that one doesn't exist, it's in one of the folders there not named data or backup for mp or sp edu.
With minimal UI you press F5 to remove the map, with F6 you regulate whether the commands "slide" should always be visible, hide or always hide. With F7 you remove the unit cards. You can take away the unit information boxes by pressing down ctrl + F2 (which should be possible with normal UI as well).
You can zoom in with your mousewheel. You can zoom in even further if you use the movie cam, but for that you need to have the battle saved as a replay first, so that only works for custom or multiplayer battles. To use it,
1) Make a shortcut to your preferred exe (either rome, bi or alex.exe).
2) Right click on the shortcut and choose properties.
3) At the very end of the "Target" field, add "-mod: eb -movie_cam" without the quotation marks. It should look like this (disregarding the install location which may vary):
Code:
"C:\Games\Rome - Total War\RomeTW.exe" -mod:eb -movie_cam
4) Hit okay, then start EB up through that shortcut and load a saved replay.
Voilà!
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