SDWebImage clearing cache

Located the source if an issue. It seems that I was deceived by the Singleton pattern used in SDImageCache. The cache for extension that is used over UIImageView is being controlled by SDWebImageManager which has an instance variable of SDImageCache. If you want to clear the cache for extension you have to call its imageCache's methods like clearDisk and clearMemory.

SDImageCache *imageCache = [SDImageCache sharedImageCache];
[imageCache clearMemory];
[imageCache clearDisk];

Don't forget to put these lines of code in your didReceiveMemoryWarning, too.