You can render images much larger than the window size. First, adjust your document window size so that you get everything in the scene that you want to see. Then in Poser 5, what you have to do is choose the Render Options command, to open up the render options dialog. There is a section in the dialog called "Image Output Settings." It defaults to "Render to main window." However, to render a larger image, choose "Render to New Window." Then, click the Match Document Window button. That will adjust the dimensions to match your window size. Finally, with the "Constrain Aspect Ratio" option checked, enter a new width or height number, and the other one will automatically adjust to match the aspect ratio of your document window.