title: jXLS jx:image ends with java.lang.IllegalArgumentException: imgBean value must contain image bytes
body: <p>I want to put an image in XLS file template with jXLS 2.2.3</p>
  
  <p>XLS template is defined as follows:</p>
  
  <p>Cell A1, added comment: 
  jx:area(lastCell="L10")</p>
  
  <p>Cell A10, added comment:
  jx:each(items="rows" var="r" lastCell="L10")</p>
  
  <p>Cell D10, add comment:
  jx:image(imgBean="r.barcodeJpgImage" imageType="JPEG" lastCell="L10")</p>
  
  <p>When I execute the code:</p>
  
  <pre><code>        ByteArrayOutputStream fos = new ByteArrayOutputStream();
          //fis is template file input stream, fos is the output
          Transformer transformer = TransformerFactory.createTransformer(fis, fos);
          AreaBuilder areaBuilder = new XlsCommentAreaBuilder(transformer);
          List&lt;Area&gt; xlsAreaList = areaBuilder.build();
          Area xlsArea = xlsAreaList.get(0);
          Context context = new Context();
          for (Map.Entry&lt;String, Object&gt; entry : beans.entrySet()) {
              context.putVar(entry.getKey(), entry.getValue());
          }
          xlsArea.applyAt(new CellRef(0,0), context);
          transformer.write();
  </code></pre>
  
  <p>I get this exception:</p>
  
  <blockquote>
    <p>Caused by: java.lang.IllegalArgumentException: imgBean value must contain image bytes (byte[])
        at org.jxls.command.ImageCommand.applyAt(ImageCommand.java:76)
        at org.jxls.area.XlsArea.applyAt(XlsArea.java:142)
        at org.jxls.command.EachCommand.applyAt(EachCommand.java:177)
        at org.jxls.area.XlsArea.applyAt(XlsArea.java:142)</p>
  </blockquote>
  
  <p>Variable <code>r.barcodeJpgImage</code> is not null and contains JPEG image bytes.</p>
  
  <p>Any idea what might be wrong?!</p>