title: issue related to apache poi
body: <p>I am facing one issue , like I have used apache POI for generating pptx powerpoint presentation so the generated ppt is opening with libra office but when i am trying to open in ms powerpoint its creating some issues like images are not displaying , which i inserted in the presentation.I am taking byte Encoded strings in the json array and i am passing it to my 
  service.Could someone help me what is the problem? Thanks</p>
  
  <h2>service</h2>
  
  <pre><code>public  Response  generatePptDocument(JSONObject json) throws JSONException{
                      JSONArray  jsonArray=json.getJSONArray("image");
                      String [] stringArray=new String[jsonArray.length()];
                      XMLSlideShow ppt = new XMLSlideShow();
                      Response result=null;
                      String uniquename=null;
                      try{
                          for(int i=0;i&lt;jsonArray.length();i++){
                              XSLFSlide slide = ppt.createSlide();
                              stringArray[i]=(String) jsonArray.get(i);
                              byte[] picture=Base64.decodeBase64(stringArray[i].substring(22));
                              int idx = ppt.addPicture(picture, XSLFPictureData.PICTURE_TYPE_PNG);
                              ppt.setPageSize(new java.awt.Dimension(1600, 600));
                              //creating a slide with given picture on it
                              XSLFPictureShape pic = slide.createPicture(idx);
                              String outputDirectory = propertyUtil.getProperty("output.save.uri");
                              SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("ddMMyyyyHHmmss");
                              String date = DATE_FORMAT.format(new Date());
                               uniquename = 1 + "-" + date + "." + "pptx";
                              String streamPath = outputDirectory+uniquename;
                            //creating a file object 
                              File file=new File(streamPath);
                              FileOutputStream out = new FileOutputStream(file);
                            //saving the changes to a file
                              ppt.write(out);
                              StringResponse  response=new StringResponse();
                              response.setUniqueName(uniquename);
                              result=Response.ok().entity(response).build();
                            }
                      }catch(JSONException e){
                          log.info("Error in json Object");
                          result=Response.status(304).entity("Error in json Object").build();
                      }
                      catch(IOException e){
                          log.info("Error while creating PPT Document");
                          result=Response.status(304).entity("Error while generation PPT").build();
                      }  
  </code></pre>