DouKaku?

import java.awt.Component
import java.awt.image._
import java.io.File;
import java.net.URL;
import javax.imageio.ImageIO;

def invert(url:String, out:String) = {
  val im = new Component{} createImage(new FilteredImageSource(
                ImageIO.read(new URL(url)).getSource,
                  new RGBImageFilter {
                    override def filterRGB(x:int,y:int,rgb:int):int = {
                      (rgb & 0xff000000 )+((rgb & 0xffffff) ^ 0xffffff)
                    }
              }))
  val bim = new BufferedImage(im.getWidth(null), im.getHeight(null),
  BufferedImage.TYPE_INT_RGB)
  val g = bim.createGraphics
  g.drawImage(im, 0, 0, null)
  g.dispose
  ImageIO.write(bim, url.split("\\.").last, new File(out))
}

invert("http://news.google.com/images/jp.gif", "test2.gif")