code: public MimeType getMimeType() {
  		if (format >= 0 && format < MIME_TYPE_STRINGS.length) {
  			if (format == FORMAT_JPEG && progressive)
  			{
  				return new MimeType("image/pjpeg");
  			}
  			return new MimeType(MIME_TYPE_STRINGS[format]);
  		} else {
  			return null;
  		}
  	}
docs: If {@link #ingest()} was successful, returns a String with the
  MIME type of the format.
  @return MIME type, e.g. <code>image/jpeg</code>