Manipulate an image without deleting its EXIF data

Question

Using imageIO, I usually have the problem of transforming an image file, and after overwriting it, it loses all of its EXIF data. Is there any way to preserve it without first extracting it, caching it, and then resetting it?

Answer 1

ImageIO do have this functionality itself, but instead of ImageIO.read you will need to use ImageReader:

ImageReader reader = ImageIO.getImageReadersBySuffix("jpg").next();

(you may want to also check if such reader exists). Then you need to set the input:

reader.setInput(ImageIO.createImageInputStream(your_imput_stream));

Now you may save your metadata:

IIOMetadata metadata = reader.getImageMetadata(0); 
                            // As far as I understand you should provide 
                            // index as tiff images could have multiple pages

And then read the image:

BufferedImage bi = reader.read(0);

When you want to save new image, you should use ImageWriter:

// I'm writing to byte array in memory, but you may use any other stream
ByteArrayOutputStream os = new ByteArrayOutputStream(255);
ImageOutputStream ios = ImageIO.createImageOutputStream(os);

Iterator<ImageWriter> iter = ImageIO.getImageWritersByFormatName("jpeg");
ImageWriter writer = iter.next();
writer.setOutput(ios);

//You may want also to alter jpeg quality
ImageWriteParam iwParam = writer.getDefaultWriteParam();
iwParam.setCompressionMode(ImageWriteParam.MODE_EXPLICIT);
iwParam.setCompressionQuality(.95f);

//Note: we're using metadata we've already saved.
writer.write(null, new IIOImage(bi, null, metadata), iwParam);
writer.dispose();

//ImageIO.write(bi, "jpg", ios); <- This was initially in the code but actually it was only adding image again at the end of the file.

As it's old topic, I guess this answer is a bit too late, but may help others as this topic is still googlable.