How to render desktop images in Cinema 4D.?

I have the 40 day Cinema 4D trial, and it's great. I'm just confused on rendering. I have all my settings set for a desktop image of my name, res. of 1366x768, and when I render it always shrinks the image size and turns out looking bad as a desktop. I've tried JPG, PNG, and BMP. I just want to know how to render images in bigger size.