Vue.js 验证码组件问题排查：看不清换一张按钮无效

To troubleshoot the issue of the 'changeImage' function not working when clicking '看不清换一张', you can try the following steps:

1. Check the path of the images in the 'imgUrlList' array. Make sure that the image files exist in the specified path.
2. Make sure that the file extension of the images in the 'imgUrlList' array matches the actual file extension of the images.
3. Check the value of the 'imgSrc' property in the Vue data. It should be initially set to the correct image source.
4. Ensure that the 'changeImage' method is correctly bound to the 'v-on:click' event in the HTML code.
5. Verify that there are no errors or warnings in the browser console. If there are any errors, fix them accordingly.
6. If the issue persists, you can try adding console.log statements inside the 'changeImage' method to check if it is being called and if the random index is being selected correctly.

By following these steps, you should be able to identify and resolve the issue with the 'changeImage' function not working when clicking '看不清换一张'.