ImageCache::flush() method?

I’d like to ask for a simple flush() method for ImageCache that would simply invalidate the cache, causing all subsequent call to image loading methods to actually reload from file.

I’m having an issue where I’m checking for an image file for modifications (by checking its last modification time at regular interval) but ImageCache relies on the filename to compute a hashcode, so it misses modifications if only the file’s content changes.

Thanks!