http://www.google.com/images?q=New%2...=1136&bih=1006
adjust as needed to modify the results you get. For example when I was looking for high res avatar images to chop up for wallpaper I would search for 1600 avatar or 1920 avatar (IE many times high res wallpaper has the RESOLUTION as part of the file name)
Play with that. Once you get used to google image search you will never have an issue finding pretty much any picture you could dream of.