Вы можете использовать JAI для сохранения изображений на диск, см. Пример:
поддержка JAI TIFF, JPEG, PNG ...
SampleModel sampleModel =
RasterFactory.createBandedSampleModel(DataBuffer.TYPE_FLOAT, width,height,1);
// Create a compatible ColorModel.
ColorModel colorModel = PlanarImage.createColorModel(sampleModel);
Raster raster = RasterFactory.createWritableRaster(sampleModel,dbuffer, new Point(0,0));
// Create a TiledImage using the float SampleModel.
TiledImage tiledImage = new TiledImage(0,0,width,height,0,0,
sampleModel,colorModel);
// Set the data of the tiled image to be the raster.
tiledImage.setData(raster);
// Save the image on a file.
JAI.create("filestore",tiledImage,"floatpattern.tif","TIFF");