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pdfbox - pdf increase size after converting to grayscale

I need to convert scanned PDF to grayscale PDF. I found 2 solutions for that.
First one is to just use renderImage
private void convertToGray() throws IOException {
File pdfFile = new File(PATH);
try (PDDocument originalPdf = PDDocument.load(pdfFile);
PDDocument doc = new PDDocument()) {
LOGGER.info("Current heap after loading file: {}", Runtime.getRuntime().totalMemory());
PDFRenderer pdfRenderer = new PDFRenderer(originalPdf);
for (int pageNum = 0; pageNum < originalPdf.getNumberOfPages(); pageNum++) {
// PDImageXObject pdImage = LosslessFactory.createFromImage(doc, bufferedImage);
BufferedImage grayImage = pdfRenderer.renderImageWithDPI(pageNum, 300F, ImageType.GRAY);
PDImageXObject pdImage = JPEGFactory.createFromImage(doc, grayImage);
float pageWight = originalPdf.getPage(pageNum).getMediaBox().getWidth();
float pageHeight = originalPdf.getPage(pageNum).getMediaBox().getHeight();
PDPage page = new PDPage(new PDRectangle(pageWight, pageHeight));
doc.addPage(page);
try (PDPageContentStream contentStream = new PDPageContentStream(doc, page)) {
contentStream.drawImage(pdImage, 0F, 0F, pageWight, pageHeight);
}
}
doc.save(NEW_PATH);
}
}
But this leads to increase size of the file (because some PDFs has less DPI than 300.
Second one is to just replace existing image with gray analog
private void convertByImageToGray() throws IOException {
File pdfFile = new File(PATH);
try (PDDocument document = PDDocument.load(pdfFile)) {
List<COSObject> objects = document.getDocument().getObjectsByType(COSName.IMAGE);
for (COSObject object : objects) {
LOGGER.info("Class: {}; {}", object.getClass(), object.toString());
}
for (int pageNum = 0; pageNum < document.getNumberOfPages(); pageNum++) {
PDPage page = document.getPage(pageNum);
replaceImage(document, page);
}
document.save(NEW_PATH);
}
}
private void replaceImage(PDDocument document, PDPage page) throws IOException {
PDResources resources = page.getResources();
Iterable<COSName> xObjectNames = resources.getXObjectNames();
if (xObjectNames != null) {
for (COSName xObjectName : xObjectNames) {
PDXObject object = resources.getXObject(xObjectName);
if (object instanceof PDImageXObject) {
PDImageXObject img1 = (PDImageXObject) object;
BufferedImage bufferedImage1 = img1.getImage();
BufferedImage grayBufferedImage = convertBufferedImageToGray(bufferedImage1);
// PDImageXObject grayImage = JPEGFactory.createFromImage(document, grayBufferedImage);
PDImageXObject grayImage = LosslessFactory.createFromImage(document, grayBufferedImage);
resources.put(xObjectName, grayImage);
}
}
}
}
private static BufferedImage convertBufferedImageToGray(BufferedImage sourceImg) {
ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_GRAY);
ColorConvertOp op = new ColorConvertOp(sourceImg.getColorModel().getColorSpace(), cs, null);
op.filter(sourceImg, sourceImg);
return sourceImg;
}
But still some files increase in size like 3 times (even they were already grayscale; interesting that int this case JPEGFactory produces larger files than LosslessFactory). All images in grayscale PDF have the same size as original ones. And I don't understand why.
Maybe there is a better way to make grayscale PDF with predictable size (except ghostscript)?
UPDATE: I've just realized that the issue is with creating PDF from image. It does not compress as well.
For example, I have dummy 1-page scan file that is less than 1 Mb. But if I get image from it (directly copying via Acrobat Reader to Paint, or via code above) it size is ~8-10 Mb depending on the method. And if I create new PDF from this image it's barely compressed. Here is example code:
File pdfFile = new File(FULL_FILE);
try (PDDocument document = PDDocument.load(pdfFile)) {
PDPage page = new PDPage();
document.addPage(page);
PDImageXObject pdImage = PDImageXObject.createFromFile("example.png", document);
try (PDPageContentStream contents = new PDPageContentStream(document, page)) {
contents.drawImage(pdImage, 0F, 0F);
}
document.save(FULL_FILE_NEW);
}

Yes LosslessFactory produces smaller files compared to JPEGFactory
In the below link there are different methods to try and achieve the same goal. Overall the best quality gray scale image was the one from Option 6, however this was by no means the fastest (I myself used Option 4). Comparisons are also provided for you to choose
This link contains possible ways to convert color images to black. It helped me a lot.
Let me know if it works for you and approve my answer if it helped.

Retrieve the page number of an image in pdf- IText

I am using the code from the below link to render the images
MyImageRenderListener - IText
Below is my try block of the Code. What I am actually doing is finding the DPI of the image and if the dpi of the image is below 300 then writing it in a text file.
NOW, I also want to write the page numbers where these images are located in the PDF. How can I obtain the Page Number of that image?
try {
String filename;
FileOutputStream os;
PdfImageObject image = renderInfo.getImage();
BufferedImage img = null;
String txtfile = "results/results.txt";
PdfDictionary imageDict = renderInfo.getImage().getDictionary();
float widthPx = imageDict.getAsNumber(PdfName.WIDTH).floatValue();
float heightPx = imageDict.getAsNumber(PdfName.HEIGHT).floatValue();
float widthUu = renderInfo.getImageCTM().get(Matrix.I11);
float heigthUu = renderInfo.getImageCTM().get(Matrix.I22);
float widthIn = widthUu/72;
float heightIn = heigthUu/72;
float imagepdi = widthPx/widthIn;
filename = String.format(path, renderInfo.getRef().getNumber(), image.getFileType());
System.out.println(filename+"-->"+imagepdi);
if(imagepdi < 300){
File file = new File("C:/Users/Abhinav/workspace/itext/results/result.txt");
if(filename != null){
if (!file.exists()) {
file.createNewFile();
}
FileWriter fw = new FileWriter(file.getAbsoluteFile(),true);
file.setReadable(true, false);
file.setExecutable(true, false);
file.setWritable(true, false);
BufferedWriter bw = new BufferedWriter(fw);
bw.write(filename);
bw.write("\r\n");
bw.close();
}
}

This is a strange question, because it is incomplete and illogical.
Why is your question incomplete?
You are using MyImageRenderListener in the context of another example, ExtractImages:
PdfReader reader = new PdfReader(filename);
PdfReaderContentParser parser = new PdfReaderContentParser(reader);
MyImageRenderListener listener = new MyImageRenderListener(RESULT);
for (int i = 1; i <= reader.getNumberOfPages(); i++) {
parser.processContent(i, listener);
}
reader.close();
In this example, you loop over every page number to examine every separate page. Hence you know the page number whenever MyImageRenderListener returns an image.
Images are stored inside a PDF as external objects (aka XObject). MyImageRenderListener returns what's stored in such a stream object (containing the bytes of the image). So far, so good.
Why is your question illogical?
Because the whole purpose of storing images in XObject is to be able to reuse the same image stream. Imagine an image of a logo. That image can be present on every page of the document. In this case, MyImageRenderListener will give you the same image (from the same stream) as many times as there are pages, but in reality, there is only one image, and it's external to the page content. It doesn't make sense for that image to "know" the page it is on: it is on every page. The same logic applies even when the image is only used on one page. That is inherent to the design of PDF: an image stream doesn't know which page it belongs to. The link between the image stream and the page exists through the /XObject entry in the /Resources of the page dictionary.
What would be an elegant way to solve this?
Create a member-variable in MyImageRenderListener, e.g.:
protected int pagenumber;
public void setPagenumber(int pagenumber) {
this.pagenumber = pagenumber;
}
Use the setter from your loop:
PdfReader reader = new PdfReader(filename);
PdfReaderContentParser parser = new PdfReaderContentParser(reader);
MyImageRenderListener listener = new MyImageRenderListener(RESULT);
for (int i = 1; i <= reader.getNumberOfPages(); i++) {
listener.setPagenumber(i);
parser.processContent(i, listener);
}
reader.close();
Now you can use pagenumber in the renderImage(ImageRenderInfo renderInfo) method. This way, you'll always know which page is being examined when this method is triggered.

Replacing images with same resource in PDFBox

I have a pdf containing 2 blank images. I need to replace both the images with 2 separate images using PDFBox. The problem is, both the blank images appear to have the same resource. So, if I replace one, the other one is replaced with the same image as well.
I followed this example and tried overriding the processOperator() method and replaced the images based on the imageHeight. However, it still ends up replacing both the images with the same image. This is my code thus far:
protected void processOperator( PDFOperator operator, List arguments ) throws IOException
{
String operation = operator.getOperation();
if( INVOKE_OPERATOR.equals(operation) )
{
COSName objectName = (COSName)arguments.get( 0 );
Map<String, PDXObject> xobjects = getResources().getXObjects();
PDXObject xobject = (PDXObject)xobjects.get( objectName.getName() );
if( xobject instanceof PDXObjectImage )
{
PDXObjectImage blankImage = (PDXObjectImage)xobject;
int imageWidth = blankImage.getWidth();
int imageHeight = blankImage.getHeight();
System.out.println("Image width >>> "+imageWidth+" height >>>> "+imageHeight);
// Check if it is blank image 1 based on height
if(imageHeight < 480){
File logo = new File("abc.jpg");
BufferedImage bufferedImage = ImageIO.read(logo);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ImageIO.write( bufferedImage, "jpg", baos );
baos.flush();
byte[] logoImageInBytes = baos.toByteArray();
baos.close();
// label will be used to replace the blank image
label = logoImageInBytes;
}
BufferedImage img = ImageIO.read(new ByteArrayInputStream(label));
BufferedImage resizedImage = Scalr.resize(img, Scalr.Method.BALANCED, Scalr.Mode.FIT_EXACT, img.getWidth(), img.getHeight());
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ImageIO.write(resizedImage, "jpg", baos);
// Replace empty image in template with the image generated from shipping label byte array
PDXObjectImage validImage = new PDJpeg(doc, new ByteArrayInputStream(baos.toByteArray()));
blankImage.getCOSStream().replaceWithStream(validImage.getCOSStream());
}
Now, when I remove the if block which checks if (imageHeight < 480), it prints the imageHeight as 30 and 470 for the blank images. However, when I add the if block, it prints the imageHeight as 480 and 1500 and never goes inside the if block because of which both the blank images end up getting replaced by the same image.
What's going on here? I'm new to PDFBox, so I am unsure if my code is correct.

While first thinking about a generic way to actually replace the existing Image by the new Images, I agree with #TilmanHausherr that a more simple solution would be to simply add an extra content stream with two images in the size / position you need covering the existing Image.
This approach is easier to implement (even generically) and less error-prone than actual replacement.
In a generic solution we do not have the Image positions beforehand. To determine them, we can use this helper class (which essentially is a rip-off of the PDFBox example PrintImageLocations):
public class ImageLocator extends PDFStreamEngine
{
private static final String INVOKE_OPERATOR = "Do";
public ImageLocator() throws IOException
{
super(ResourceLoader.loadProperties("org/apache/pdfbox/resources/PDFTextStripper.properties", true));
}
public List<ImageLocation> getLocations()
{
return new ArrayList<ImageLocation>(locations);
}
protected void processOperator(PDFOperator operator, List<COSBase> arguments) throws IOException
{
String operation = operator.getOperation();
if (INVOKE_OPERATOR.equals(operation))
{
COSName objectName = (COSName) arguments.get(0);
Map<String, PDXObject> xobjects = getResources().getXObjects();
PDXObject xobject = (PDXObject) xobjects.get(objectName.getName());
if (xobject instanceof PDXObjectImage)
{
PDXObjectImage image = (PDXObjectImage) xobject;
PDPage page = getCurrentPage();
Matrix matrix = getGraphicsState().getCurrentTransformationMatrix();
locations.add(new ImageLocation(page, matrix, image));
}
else if (xobject instanceof PDXObjectForm)
{
// save the graphics state
getGraphicsStack().push((PDGraphicsState) getGraphicsState().clone());
PDPage page = getCurrentPage();
PDXObjectForm form = (PDXObjectForm) xobject;
COSStream invoke = (COSStream) form.getCOSObject();
PDResources pdResources = form.getResources();
if (pdResources == null)
{
pdResources = page.findResources();
}
// if there is an optional form matrix, we have to
// map the form space to the user space
Matrix matrix = form.getMatrix();
if (matrix != null)
{
Matrix xobjectCTM = matrix.multiply(getGraphicsState().getCurrentTransformationMatrix());
getGraphicsState().setCurrentTransformationMatrix(xobjectCTM);
}
processSubStream(page, pdResources, invoke);
// restore the graphics state
setGraphicsState((PDGraphicsState) getGraphicsStack().pop());
}
}
else
{
super.processOperator(operator, arguments);
}
}
public class ImageLocation
{
public ImageLocation(PDPage page, Matrix matrix, PDXObjectImage image)
{
this.page = page;
this.matrix = matrix;
this.image = image;
}
public PDPage getPage()
{
return page;
}
public Matrix getMatrix()
{
return matrix;
}
public PDXObjectImage getImage()
{
return image;
}
final PDPage page;
final Matrix matrix;
final PDXObjectImage image;
}
final List<ImageLocation> locations = new ArrayList<ImageLocation>();
}
(ImageLocator.java)
In contrast to the example class this helper stores the locations in a list instead of printing them.
We now can cover existing images using code like this:
try ( InputStream resource = getClass().getResourceAsStream("sample.pdf");
InputStream left = getClass().getResourceAsStream("left.png");
InputStream right = getClass().getResourceAsStream("right.png");
PDDocument document = PDDocument.load(resource) )
{
if (document.isEncrypted())
{
document.decrypt("");
}
PDJpeg leftImage = new PDJpeg(document, ImageIO.read(left));
PDJpeg rightImage = new PDJpeg(document, ImageIO.read(right));
// Locate images
ImageLocator locator = new ImageLocator();
List<?> allPages = document.getDocumentCatalog().getAllPages();
for (int i = 0; i < allPages.size(); i++)
{
PDPage page = (PDPage) allPages.get(i);
locator.processStream(page, page.findResources(), page.getContents().getStream());
}
// cover images
for (ImageLocation location : locator.getLocations())
{
// Decide on a replacement
PDRectangle cropBox = location.getPage().findCropBox();
float center = (cropBox.getLowerLeftX() + cropBox.getUpperRightX()) / 2.0f;
PDJpeg image = location.getMatrix().getXPosition() < center ? leftImage : rightImage;
AffineTransform transform = location.getMatrix().createAffineTransform();
PDPageContentStream content = new PDPageContentStream(document, location.getPage(), true, false, true);
content.drawXObject(image, transform);
content.close();
}
document.save(new File(RESULT_FOLDER, "sample-changed.pdf"));
}
(OverwriteImage)
This sample covers all images on the left half of their respective page with left.png and all others with right.png.

I have no implementation or example, but I want to illustrate you a possible way to do what you want by the following steps:
Since you need 2 Images (lets tell them imageA and imageB) in the pdf instead of 1 (which is the blank one). You have to add both of them to the pdf.
save the file temporary - optional, it could work without rewriting the pdf
reopen the file - optional, if you don't need step 2, you also don't need this step
Then replace the blank image with imageA or imageB
Remove the blank image from the pdf
Save the pdf

Java - How to add a JLabel that contains an image to a pdf file in iText

I want to add an image which is retrieved from the mysql db and print it on a pdf file in iText java. The image retrieved from the db is stored in the lblimg. How do I achieve that in java ?
Here's my partial code:
String filename = null;
int s = 0;
byte[] person_img = null;
uploadbtn = new JButton("Upload a Photo");
uploadbtn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JFileChooser chooser = new JFileChooser();
chooser.showOpenDialog(null);
File f = chooser.getSelectedFile();
String filename = f.getAbsolutePath();
try{
File img = new File(filename);
FileInputStream fis = new FileInputStream(img);
ByteArrayOutputStream bos = new ByteArrayOutputStream();
byte[] buf = new byte[1024];
for(int readNum; (readNum = fis.read(buf)) != -1;){
bos.write(buf, 0, readNum);
}
person_img = bos.toByteArray();
fis.close();
}catch(Exception e1){
e1.printStackTrace();
}
}
});
// Partial code for adding image to db
stt.setBytes(8, person_img);
// Partial codes for retrieving image from db
byte[] imageData = rs.getBytes("Image");
format = new ImageIcon(imageData);
lblimg.setIcon(format);
//Creating the document and adding the lblimg (which contains the image retrieved from the db). PLEASE HELP HERE. I CANNOT ADD THE IMAGE TO PDF document.
Document doc = new Document();
PdfWriter.getInstance(doc, new FileOutputStream("Report.pdf"));
doc.open();
doc.add(new Paragraph( // img to be added here ));
Update 1 by Bruno Lowagie
Snippet taken from the full code:
try {
Image i = Image.getInstance((PdfTemplate) lblimg.getIcon());
Document doc = new Document();
PdfWriter.getInstance(doc, new FileOutputStream("Report.pdf"));
doc.open();
Image img = Image.getInstance("ja.png");
doc.add(img);
doc.add(i);
doc.add(new Paragraph("Employee Information", FontFactory.getFont(FontFactory.TIMES_BOLD,18, Font.BOLD, BaseColor.RED)));
doc.add(new Paragraph("______________________________________________________________________________"));
doc.add(new Paragraph("Employee ID is " + val1));
doc.add(new Paragraph("First Name is " + val2 + "\t\t" + " Last Name is " + val3));
doc.add(new Paragraph("Job Position " + val4));
doc.add(new Paragraph("Allowances allowed " + val5));
doc.add(new Paragraph("Salary " + val10));
JOptionPane.showMessageDialog(null, "Report Saved");
doc.close();
} catch(Exception e1) {
e1.printStackTrace();
}
As getIcon returns a javax.swing class and as PdfTemplate is an iText class extending the PdfContentByte class that contains a ByteBuffer of PDF syntax, a ClassCastException is thrown here: (PdfTemplate) lblimg.getIcon()
Update 2 by Bruno Lowagie
The actual question was posted as a comment: How do I retrieve an image which is in a JLabel and add it on a PDF? This question is answered in update 3 of my answer.

Assuming that this contains an image:
byte[] imageData = rs.getBytes("Image");
In other words: assuming that imageData is a valid JPEG, JPEG2000, GIF, PNG, BMP, WMF, TIFF or JBIG2 image, then you can create a com.itextpdf.text.Image object like this:
Image img = Image.getInstance(imageData);
Once you have this img instance, you can add it to the document like this:
document.add(img);
I don't understand why you'd create an ImageIcon instance. Nor is it clear why you refer to a Paragraph object.
Update 1:
Now that I see your full code, I see a very strange line:
Image i = Image.getInstance((PdfTemplate) lblimg.getIcon());
You are casting a javax.swing object to an iText object. This can never work. You should get a ClassCastException at this point in your code.
I also see that you know how to add an image from a file:
Image img = Image.getInstance("ja.png");
doc.add(img);
When you don't have a path to a file, the fastest way you'll find alternative getInstance() methods, is by consulting the Javadoc API documentation: http://api.itextpdf.com/itext/com/itextpdf/text/Image.html#getInstance(byte[])
Update 2:
I have updated the question so that it contains the relevant code. As explained in my answer (that unfortunately wasn't accepted), the following line throws a ClassCastException:
Image i = Image.getInstance((PdfTemplate) lblimg.getIcon());
This exception is caught like this:
} catch(Exception e1) {
e1.printStackTrace();
}
Hence all the code starting with the following line is skipped:
Document doc = new Document();
As a result, no document is created. This is not an iText problem. This is a case of bad exception handling.
Update 3:
Finally, the real question is asked in a comment: In simple words: How to I retrieve an image which is in a JLabel and add it on a PDF?
Again it turns out that I have already answered that question. I referred to the Javadoc API documentation for the Image class. We find the following getInstance() method: http://api.itextpdf.com/itext/com/itextpdf/text/Image.html#getInstance(java.awt.Image, java.awt.Color)
In other words, we can create an iText Image object using a Java Image object. You have the following line in your code:
ImageIcon format = new ImageIcon(imageData);
Or, in your case, you could try something like:
ImageIcon format = (ImageIcon)lblimg.getIcon();
You can get a java.awt.Image object from this ImageIcon like this:
java.awt.Image awtImage = format.getImage();
As per the iText API documentation, you can create an iText image like this:
Image img = Image.getInstance(awtImage, null);

How do you access an attachment stored as MIME Part?

It seems to me there are two ways to store an attachment in a NotesDocument.
Either as a RichTextField or as a "MIME Part".
If they are stored as RichText you can do stuff like:
document.getAttachment(fileName)
That does not seem to work for an attachment stored as a MIME Part. See screenshot
I have thousands of documents like this in the backend. This is NOT a UI issue where I need to use the file Download control of XPages.
Each document as only 1 attachment. An Image. A JPG file. I have 3 databases for different sizes. Original, Large, and Small. Originally I created everything from documents that had the attachment stored as RichText. But my code saved them as MIME Part. that's just what it did. Not really my intent.
What happened is I lost some of my "Small" pictures so I need to rebuild them from the Original pictures that are now stored as MIME Part. So my ultimate goal is to get it from the NotesDocument into a Java Buffered Image.
I think I have the code to do what I want but I just "simply" can't figure out how to get the attachment off the document and then into a Java Buffered Image.
Below is some rough code I'm working with. My goal is to pass in the document with the original picture. I already have the fileName because I stored that out in metaData. But I don't know how to get that from the document itself. And I'm passing in "Small" to create the Small image.
I think I just don't know how to work with attachments stored in this manner.
Any ideas/advice would be appreciated! Thanks!!!
public Document processImage(Document inputDoc, String fileName, String size) throws IOException {
// fileName is the name of the attachment on the document
// The goal is to return a NEW BLANK document with the image on it
// The Calling code can then deal with keys and meta data.
// size is "Original", "Large" or "Small"
System.out.println("Processing Image, Size = " + size);
//System.out.println("Filename = " + fileName);
boolean result = false;
Session session = Factory.getSession();
Database db = session.getCurrentDatabase();
session.setConvertMime(true);
BufferedImage img;
BufferedImage convertedImage = null; // the output image
EmbeddedObject image = null;
InputStream imageStream = null;
int currentSize = 0;
int newWidth = 0;
String currentName = "";
try {
// Get the Embedded Object
image = inputDoc.getAttachment(fileName);
System.out.println("Input Form : " + inputDoc.getItemValueString("form"));
if (null == image) {
System.out.println("ALERT - IMAGE IS NULL");
}
currentSize = image.getFileSize();
currentName = image.getName();
// Get a Stream of the Imahe
imageStream = image.getInputStream();
img = ImageIO.read(imageStream); // this is the buffered image we'll work with
imageStream.close();
Document newDoc = db.createDocument();
// Remember this is a BLANK document. The calling code needs to set the form
if ("original".equalsIgnoreCase(size)) {
this.attachImage(newDoc, img, fileName, "JPG");
return newDoc;
}
if ("Large".equalsIgnoreCase(size)) {
// Now we need to convert the LARGE image
// We're assuming FIXED HEIGHT of 600px
newWidth = this.getNewWidth(img.getHeight(), img.getWidth(), 600);
convertedImage = this.getScaledInstance(img, newWidth, 600, false);
this.attachImage(newDoc, img, fileName, "JPG");
return newDoc;
}
if ("Small".equalsIgnoreCase(size)) {
System.out.println("converting Small");
newWidth = this.getNewWidth(img.getHeight(), img.getWidth(), 240);
convertedImage = this.getScaledInstance(img, newWidth, 240, false);
this.attachImage(newDoc, img, fileName, "JPG");
System.out.println("End Converting Small");
return newDoc;
}
return newDoc;
} catch (Exception e) {
// HANDLE EXCEPTION HERE
// SAMLPLE WRITE TO LOG.NSF
System.out.println("****************");
System.out.println("EXCEPTION IN processImage()");
System.out.println("****************");
System.out.println("picName: " + fileName);
e.printStackTrace();
return null;
} finally {
if (null != imageStream) {
imageStream.close();
}
if (null != image) {
LibraryUtils.incinerate(image);
}
}
}

I believe it will be some variation of the following code snippet. You might have to change which mimeentity has the content so it might be in the parent or another child depending.
Stream stream = session.createStream();
doc.getMIMEEntity().getFirstChildEntity().getContentAsBytes(stream);
ByteArrayInputStream bais = new ByteArrayInputStream(stream.read());
return ImageIO.read(bais);
EDIT:
session.setConvertMime(false);
Stream stream = session.createStream();
Item itm = doc.getFirstItem("ParentEntity");
MIMEEntity me = itm.getMIMEEntity();
MIMEEntity childEntity = me.getFirstChildEntity();
childEntity.getContentAsBytes(stream);
ByteArrayOutputStream bo = new ByteArrayOutputStream();
stream.getContents(bo);
byte[] mybytearray = bo.toByteArray();
ByteArrayInputStream bais = new ByteArrayInputStream(mybytearray);
return ImageIO.read(bais);

David have a look at DominoDocument,http://public.dhe.ibm.com/software/dw/lotus/Domino-Designer/JavaDocs/XPagesExtAPI/8.5.2/com/ibm/xsp/model/domino/wrapped/DominoDocument.html
There you can wrap every Notes document
In the DominoDocument, there such as DominoDocument.AttachmentValueHolder where you can access the attachments.
I have explained it at Engage. It very powerful
http://www.slideshare.net/flinden68/engage-use-notes-objects-in-memory-and-other-useful-java-tips-for-x-pages-development