private void writeImage(PDDocument document, String imageFormat, String outputPrefix, int imageType, int resolution)
throws IOException
{
List pages = document.getDocumentCatalog().getAllPages();
PDPage page = (PDPage)pages.get( 0 );
BufferedImage image = page.convertToImage(imageType, resolution);
String fileName = outputPrefix + 1;
System.out.println( "Writing: " + fileName + "." +imageFormat);
ImageIOUtil.writeImage(image, imageFormat, fileName, imageType, resolution);
}