Cloudflare's selective cache invalidation: still playing hide-and-seek with my images?

The challenge with immediate cache invalidation for frequently updated assets, especially user avatars, often comes down to a combination of origin server header configuration and Cloudflare's revalidation logic. While selective cache invalidation via the API should work for specific URLs, if the new content isn't showing, it indicates a disconnect in how the cache is being instructed or how the new version is being identified.

• Implement Cache Busting: For dynamic images like user avatars, the most reliable approach is to change the URL of the image whenever it's updated. This forces all caches (browser, CDN, proxy) to fetch the new version, as it's seen as a completely new resource. You can achieve this by appending a version number or timestamp to the filename or as a query parameter (e.g., profile.jpg?v=123456789 or profile_123456789.jpg). This bypasses any `Cloudflare cache control` complexities entirely for that specific URL.
• Optimize Origin `Cache-Control` Headers: Ensure your origin server is sending appropriate headers for these specific image paths. For assets that need immediate updates, `Cache-Control: no-cache, must-revalidate, max-age=0` is a strong directive. This tells Cloudflare and other caches to revalidate with the origin for every request before serving a cached version. Avoid `no-store` unless you genuinely want to prevent *any* form of caching, as it can be overly aggressive for images that might still benefit from revalidation.
• Verify ETag and Last-Modified Headers: Cloudflare relies on `ETag` and `Last-Modified` headers from your origin to determine if a cached asset is still fresh during revalidation. Ensure these headers are correctly generated and updated by your server when an image changes. If they don't change, Cloudflare will assume the cached version is still valid.
• Check Cloudflare Page Rules: Review your Cloudflare Page Rules to ensure no rule is inadvertently setting a long `Edge Cache TTL` for the paths where your profile images reside. A conflicting Page Rule can override your origin's `Cache-Control` headers. For these specific paths, you might consider setting "Cache Level: Bypass" or a very short "Edge Cache TTL" if cache busting isn't feasible, though cache busting is generally preferred for this use case to ensure a robust `CDN caching strategy`.

yeah, the `no-cache, must-revalidate` is definitely the right approach from the origin side. but I sometimes wonder if Cloudflare's own Edge Cache TTL can still kinda win out for a few seconds initially, even with the API call to invalidate, before it actually revalidates everywhere...