graphic tweaks?

[roarzola]

Hey, I am a complete newbie when it comes to things like this and wasn't sure where else to ask..

Anyways I play a game called America's Army, and I found some pic's online where some one had made some tweaks that really changed the look of the game;

Map 1 (tweaks)
Map 1 (stock)

Map 2 (tweaks)
Map 2 (stock)

I was told that it was just some small 'D3D tweaks' using some kind of program.. But I have looked and fiddled around with a few programs, but no matter what I tried nothing came close to the changes like in the above pics.. Then again I am pretty clueless when it comes to things like this, but I am interested in learning how it could be done.. I was just hoping someone here might be able to explain to me how someone could achieve such changes? A little help would be much appreciated...