diff --git a/readme.md b/readme.md
index 944926f..c8f69d1 100644
--- a/readme.md
+++ b/readme.md
@@ -158,6 +158,8 @@ public class Test {
         // 标准验证码生成器
         ImageCaptchaGenerator imageCaptchaGenerator = new MultiImageCaptchaGenerator(imageCaptchaResourceManager, true);
         // 生成旋转验证码 图片类型为 webp
+        // 注意 tianai-captcha 后面默认删除了生成webp格式图片需要用户自定义添加webp转换的工具，需要用户自定义添加和扩展
+        // 参考 https://bitbucket.org/luciad/webp-imageio
         SliderCaptchaInfo slideImageInfo = sliderCaptchaGenerator.generateSlideImageInfo(GenerateParam.builder()
                 .type(CaptchaTypeConstant.ROTATE)
                 .sliderFormatName("webp")