Luminaa, In the Firefly render options window, there's a box that allows you to control maximum texture resolutions during rendering. At default it's set at "4096". If you wanna render at 1024 x 1024 then you can set that box to "1024". I've been told that setting the texture resolution larger than your final render output (like 4096 when you're rendering 1024x1024) won't make much of a difference in render quality. That might be open to debate.