code: protected BodyPart handleImageBinaryPart(MimePart image, String contentType) throws IOException, MessagingException {
          ByteArrayOutputStream bos = new ByteArrayOutputStream();
          FileCopyUtils.copy(image.getInputStream(), bos);
          String base64 = Base64.encodeBase64String(bos.toByteArray());
          return new BodyPart(base64, contentType);
      }
docs: Construct base64 body part from image data.
  @param image
  @param contentType
  @return
  @throws IOException