//add first slide
Slide s1 = ppt.createSlide();
SlideMaster master = ppt.getSlidesMasters()[0];
Fill fill = master.getBackground().getFill();
int idx = ppt.addPicture(new File("data/background.jpg"), Picture.JPEG);
fill.setFillType(Fill.FILL_PICTURE);
fill.setPictureData(idx);
//save changes in a file
FileOutputStream out = new FileOutputStream("data/AddBG_Apache.ppt");
ppt.write(out);
out.close();