此为水印图片的载入程序

using system.drawing;
using system.drawing.imaging;
context.response.contenttype="image/jpeg";
string path=context.request.querystring["path"];
string vpath =context.server.mappath(path);
using(image img=image.fromfile(vpath))
{
string upath =context.server.mappath("1.jpg");
using(image uimg=image.fromfile(upath))
{
using(graphics g=graphics.fromfile(img))
{
g.drawimage(uimg,0,0);
img.save(context.response.outputstream,imageformat.jpeg);//绘制图片输出到响应流
}
}
}