import java.applet.Applet;
import java.awt.Graphics;
import java.awt.Image;


@SuppressWarnings("serial")
public class BackgroundImage extends Applet{
    Image picture;
    boolean ImageLoaded=false;
    @SuppressWarnings("deprecation")
    public void init(){
        picture=getImage(getCodeBase(),"F:\\图片\\21.jpg");
        Image offscreeImage=createImage(size().width, size().height);
        Graphics offscreenGC=offscreeImage.getGraphics();
        offscreenGC.drawImage(picture, 0, 0, this);
        ImageLoaded=true;
    }
    public void paint(Graphics g){
        if(ImageLoaded){
            showStatus("Done");
        }else
          showStatus("Loading image");
    }
    public boolean imageUpdate(Image img,int infoflages,int x,int y,int w,int h){
        if(infoflages==ALLBITS){
            ImageLoaded=true;
            repaint();
            return false;
        }else
            return true;
    }
}

这是你自己写的代码？

这工程也不全，你这是要在小程序里给铺上背景图片吧，你这种写法的话试试把图片直接放在工程文件里面然后把路径都去掉只留图片名试试看

或者你试试这样

import java.awt.*;
import java.awt.geom.*;

import javax.swing.*;
public class BackgroundImage extends JFrame
{
/**
     * 
     */
    private static final long serialVersionUID = 1207275504054549999L;
    private Image img;

    public BackgroundImage(){

               img=getToolkit().getImage(getClass().getResource("E:/images/s.jpg"));
    }

   public void paint(Graphics g)
{
g.setClip(new Rectangle2D.Float(0,0,500,350));
g.drawImage(img,0,0,this); }
@SuppressWarnings("unused")
public static void main(String[] args)
{
BackgroundImage yh=new BackgroundImage();
}
}

也许是你路径用中文的原因