iOS拍照后使用该图片（获取照片的ALasset传到相册）

-(void)imagePickerController:(UIImagePickerController*)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
NSString *type = [info objectForKey:UIImagePickerControllerMediaType];
if ([type isEqualToString:@"public.image"])
{
//先把图片转成NSData
UIImage* image = [info objectForKey:@"UIImagePickerControllerOriginalImage"];
ALAssetsLibrary *library  = [[ALAssetsLibrary alloc] init];
[library writeImageToSavedPhotosAlbum:[image CGImage] orientation:(ALAssetOrientation)[image imageOrientation] completionBlock:^(NSURL *assetURL, NSError *error){
if (error) {
// TODO: error handling
} else {
[library  assetForURL:assetURL resultBlock:^(ALAsset *asset) {
[self.selectPhotos addObject:asset];
[_imageCollection reloadData];
} failureBlock:^(NSError *error) {

}];
}
}];
}
}