Help! how do i make a picture fill up the entire page on googledocs?

using google docs, i wants to put a picture from google images from my background then write my text over it. when i paste the picture on my pg, when it gets a certain size it goes to the next page how do i get it to not do this?? please,thanks!|||first, download the image to the desktop. then right click on the slide and it will say change background. click browse and the picture will come up. select it and there you go.