code: public static boolean isImage(String suffix) {
          if (null != suffix && !"".equals(suffix) && suffix.contains(".")) {
              String regex = "(.*?)(?i)(jpg|jpeg|png|gif|bmp|webp)";
              return isMatch(regex, suffix);
          }
          return false;
      }
docs: Verify that the suffix is a picture format.
  
  @param suffix filename suffix
  @return verify that success returns true, and the failure returns false.