system.io.stream streamobject = upfile.inputstream;

　　system.io.filestream mystream = new system.io.filestream(upfile.filename,system.io.filemode.open,system.io.fileaccess.read);         

　　system.drawing.image.getthumbnailimageabort mycallback =

　　new system.drawing.image.getthumbnailimageabort(thumbnailcallback);

　　system.drawing.image img1 = system.drawing.image.fromstream(streamobject);

　　system.drawing.image timg = img1.getthumbnailimage(100,100,mycallback,system.intptr.zero);

　　timg.save(response.outputstream,system.drawing.imaging.imageformat.jpeg);