Mommy, where do stocks come from?

[inasadYBFC]

the title is self explanitory. basically I want to learn how to do stock sigs except evryone elses are like a million times better than mine XD anyone wanna point me in the right direction to get some good ones?

[Humanbomb]

http://planetrenders.net/forums/index.php?s=4e2ea1877d21df9aaf385320259bb0a9&showforum=151

[lokifeyson]

are you looking for pics of landscapes and cities type stuff or characters and people? :)

[shaothemerciful]

Okay, I'm about to ask another noob question (god, feeling this dumb never seems to get old...) after I have a stock image, what type of steps do I go through to remove or reduce what amounts to the "render" in that image, so that I mostly get background?