public  void doIt(String[] args) throws IOException 
{
        if( args.length != 3 )
        {
            usage();
        }
        else 
        {
            PDDocument document = null;
            try
            {
                document = PDDocument.load( args[0] );
                if( document.isEncrypted() )
                {
                    throw new IOException( "Encrypted documents are not supported for this example" );
                }
                List allpages = new ArrayList();
                document.getDocumentCatalog().getPages().getAllKids(allpages);
                int numberOfPages = allpages.size();
                for (int i=0; i <  numberOfPages; i++)
                {
                    PDPage apage = (PDPage) allpages.get(i);
                    List annotations = apage.getAnnotations();
                    PDAnnotationRubberStamp rubberStamp = new PDAnnotationRubberStamp();
                    rubberStamp.setName(PDAnnotationRubberStamp.NAME_TOP_SECRET);
                    rubberStamp.setRectangle(new PDRectangle(100,100));
                    rubberStamp.setContents("A top secret note");
                    // Create a PDXObjectImage with the given jpg
                    FileInputStream fin = new FileInputStream( args[2] );
                    PDJpeg mypic = new PDJpeg(document,fin);
                    //Define and set the target rectangle
                    PDRectangle myrect = new PDRectangle();
                    myrect.setUpperRightX(275);
                    myrect.setUpperRightY(575);
                    myrect.setLowerLeftX(250);
                    myrect.setLowerLeftY(550);
                    // Create a PDXObjectForm
                    PDStream formstream = new PDStream(document);
                    OutputStream os = formstream.createOutputStream();
                    PDXObjectForm form = new PDXObjectForm(formstream);
                    form.setResources(new PDResources());
                    form.setBBox(myrect);
                    form.setFormType(1);
                    // adjust the image to the target rectangle and add it to the stream
                    drawXObject(mypic, form.getResources(), os, 250, 550, 25, 25);
                    os.close();
                    PDAppearanceStream myDic = new PDAppearanceStream(form.getCOSStream());
                    PDAppearanceDictionary appearance = new PDAppearanceDictionary(new COSDictionary());
                    appearance.setNormalAppearance(myDic);
                    rubberStamp.setAppearance(appearance);
                    rubberStamp.setRectangle(myrect);
                    //Add the new RubberStamp to the document
                    annotations.add(rubberStamp);
                }
                document.save( args[1] );
            }
            catch(COSVisitorException exception) 
            {
                System.err.println("An error occured during saving the document.");
                System.err.println("Exception:"+exception);
            }
            finally
            {
                if( document != null )
                {
                    document.close();
                }
            }
        }
}

Add a rubber stamp with an jpg image to every page of the given document.

 public static  void main(String[] args) throws Exception 
{
        RubberStampWithImage rubberStamp = new RubberStampWithImage();
        rubberStamp.doIt(args);
}

This creates an instance of RubberStampWithImage.