If you are caching it both in memory and disc, for example:
ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(getApplicationContext())
.memoryCache(new UsingFreqLimitedMemoryCache(2 * 1024 * 1024))
.discCache(new UnlimitedDiscCache(cacheDir))
.........
Ensure you remove it from both of them, then reload your image view.
MemoryCacheUtils.removeFromCache(url, ImageLoader.getInstance().getMemoryCache());
DiscCacheUtils.removeFromCache(url, ImageLoader.getInstance().getDiscCache());