code: public boolean mediaIsImage() {
          String contentType = this.getContentType();
          return contentType != null && this.media != null && contentType.startsWith("image") && !contentType.equals("image/gif");
      }
docs: Method to check whether media in the {@link CTInboxMessageContent} object is an image.
  @return true if the media type is image
  false if the media type is not an image