New JEPG image size (disk size) is too low?

Question

Hi,
I am creating new JEPG image using JAI. But the resultant JEPG's size (disk size) is too less than the source image.
How to create a new JEPG with the size equals to the source image?
I guess some where in middle the compression is taking place. How to avoid it?
Thnaks in advance.

Answer 1

post some code ... with code tags
as just reading a jpeg image using JAI and rewriting it back doesn't involve re-compression ... doing something wrong some place.
   File imageFile = new File(filename);
                try {
                Iterator readers = ImageIO.getImageReadersByFormatName("jpeg2000");
                ImageReader imageReader = (ImageReader)readers.next();
                ImageInputStream imageInputStream = ImageIO.createImageInputStream(imageFile);
                imageReader.setInput(imageInputStream, true);
                ImageReadParam imageReadParam = imageReader.getDefaultReadParam();
                int imageIndex = 0;
                Rectangle rectangle = new Rectangle(0, 0,(int)pan2.getWidth(), (int)pan2.getHeight());
                //Rectangle rectangle = new Rectangle(0, 0,1000, 1000);
                imageReadParam.setSourceRegion(rectangle);
                image2 = imageReader.read(imageIndex, imageReadParam);this to read a image
Iterator writers = ImageIO.getImageWritersByFormatName("jpg");
                         ImageWriter writer = (ImageWriter) writers.next();
                         Once an ImageWriter has been obtained, its destination must be set to an ImageOutputStream:                                        
                         File f = new File(x+".jpg");
                                        try
                         ImageOutputStream ios = ImageIO.createImageOutputStream(f);
                         writer.setOutput(ios);
                                        writer.write(im[x]);
                         ios.close();and this to write the image back on the disk