ALAssetsLibraryChangedNotification

gistfile1.m

-(void)startMonitor{
    //[ALAssetsLibrary disableSharedPhotoStreamsSupport];
    [self requireAssetsLibraryAuthorization];
    
    self.assetsLibrary = [[ALAssetsLibrary alloc] init];
    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(assetsChanged:) name:ALAssetsLibraryChangedNotification object:nil];
    [self.assetsLibrary writeImageToSavedPhotosAlbum:nil metadata:nil completionBlock:^(NSURL *assetURL, NSError *error){}];
}

-(void)assetsChanged:(NSNotification *)notification{
    void(^EnumerateGroupBlock)(ALAssetsGroup *group, BOOL *stop) = ^(ALAssetsGroup *group, BOOL *stop){
        [group setAssetsFilter:[ALAssetsFilter allPhotos]];
        [group enumerateAssetsWithOptions:NSEnumerationReverse usingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop) {
        }];
    };
    [self.assetsLibrary enumerateGroupsWithTypes:ALAssetsGroupSavedPhotos usingBlock:EnumerateGroupBlock failureBlock:NULL];
    
    NSDictionary *userInfo = notification.userInfo;
    NSSet *updateAssets = userInfo[ALAssetLibraryUpdatedAssetsKey];
    if (updateAssets.count>0) {
        [[updateAssets allObjects] enumerateObjectsUsingBlock:^(NSURL *url, NSUInteger idx, BOOL *stop) {
            [self.assetsLibrary assetForURL:url resultBlock:^(ALAsset *asset) {
                UIImage *image = [UIImage imageWithCGImage:asset.thumbnail];
                DLog(@"%@",image);
            } failureBlock:^(NSError *error) {
                ELog(error);
            }];
        }];
    }
}