I'm playing an old, open source, programming, fleet battle game called GalaxyHack (http://galaxyhack.sourceforge.net/) at the moment. 

In GalaxyHack, spaceships are sprites and you can add graphics just by adding a .png graphic file of the appropriate dimensions.  You can also download and upload custom fleets.  (You can probably already see where this is going).

If I were to make ships in GalCiv2, take screenshots, and crop the spaceship, would it be legal to redistribute it as a sprite?

(My guess is "no" sadly, but I thought I'd ask...)