I use a UIWebView to load a local html, and there is a PNG file inside the html created by Objc.

After the PNG file has been modified, I reload the html in UIWebView, but the image doesn't change. However, **if I quit the app and reopen it, the image file will be changed to the new one.**

I have checked the PNG file in Documents with Finder, so I'm sure it has been modified, but the old one is still in UIWebView.

So, as I think that it's a UIWebView cache problem, I've tried:

* `[[NSURLCache sharedURLCache] removeAllCachedResponses];`
* `[_webView loadRequest:[NSURLRequest requestWithURL:[NSURL fileURLWithPath:url isDirectory:NO ] cachePolicy:NSURLRequestReloadIgnoringLocalAndRemoteCacheData timeoutInterval:1]];` or `NSURLRequestReloadIgnoringCacheData`

None of them works, and I can't change the filename, because the PNG file is used in a lot of places (other html and objc code).

I've tried this too:
`some.png?r=randomNumber`
but it can't be showed.

**How do I clear the UIWebView cache when using a local image file inside a local html?**