//Her sker alt samling af tif filer, ud fra den liste man får fra hashmappen.
    public void merge() throws IOException {
        List<String> tifs = new ArrayList<>(fileList.keySet());
        Collections.sort(tifs);

        for (String key : tifs) {
            List<File> files = fileList.get(key);

            // Sorter når er et behov for at listen er sorteret, ikke mens der hentes ud
            Collections.sort(files);

//        int numTifs = files.length;  // 2 eller flere sider
            int numTifs = files.size();
            BufferedImage image[] = new BufferedImage[numTifs];
            for (File page : files) {
                SeekableStream ss = new FileSeekableStream(page);
                ImageDecoder decoder = ImageCodec.createImageDecoder("tiff", ss, null);
                PlanarImage pi = new NullOpImage(decoder.decodeAsRenderedImage(0), null, null, OpImage.OP_IO_BOUND);
                image[files.indexOf(page)] = pi.getAsBufferedImage();
                ss.close();
            }

            TIFFEncodeParam params = new TIFFEncodeParam();
            params.setCompression(TIFFEncodeParam.COMPRESSION_DEFLATE);
            //Her skal det stå folderName
            OutputStream out = new FileOutputStream(too.getPath() + "\\" + key + ".tif");
            ImageEncoder encoder = ImageCodec.createImageEncoder("tiff", out, params);
            List<BufferedImage> list = new ArrayList<BufferedImage>(image.length);
            for (int i = 1; i < image.length; i++) {
                list.add(image[i]);
            }
            params.setExtraImages(list.iterator());
            encoder.encode(image[0]);
            out.close();
        }
        JOptionPane.showMessageDialog(rootPane, "Done!");
    }